z20 is a lite version of the d20 roleplaying game built upon a Microlite20 core. For more info, see About z20.

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GM Content





There are 3 stats: Strength, Dexterity, and Mind. These each provide a stat modifier (STR, DEX, or MIND) equal to (stat score - 10)/2, round down.

Character Creation: Roll 4d6, drop lowest dice. Total remaining 3 dice and allocate to one of the stats. Repeat for remaining stats.

Advancement: Occasionally, the GM will hand out another level to all characters. At every 3rd level (3,6,9,etc.), +1 to the stat of your choice.

Stat mods: Rather than forcing a player to recalculate all the details affected by a changed stat score, most game-time effects give a stat mod instead. Stat mods are either str, dex, mind. Regardless of stat type, each negative mod gives:

In addition, each mod has a specific "special effect":

+mods have an unlimited equivalent positive effect, countering an equal number of -mods of the same stat. If a STAT is ever effectively reduced to less than -5, the character is left debilitated.

There are two other mod types: -all mods, which give -1 to attacks and -1 to all STATs (including special effects); and -saves mods, which impose a -1 on all saves (only). All mods are cumulative (stack) with each other.

Stat damage: If a stat takes enough damage to reduce the corresponding STAT bonus, take a -stat mod instead until the damage is healed. If damage is ever >= the Stat score, the character is dead/paralyzed/unconscious for Strength/Dexterity/Mind, respectively. Stat drain works as stat damage except it does not heal normally over time (though it can be healed magically).




BAB: +3 every 4 clvls (so +1 at clvls 2,3,4,6,7,8,10...)
HP: +4 each clvl
Skill bonus:: +3 Communication
Armor/Shield: up to Medium armor; up to Heavy shields.
Ability: Divine spellcasting from the Cleric spell list (see Magic).
Ability: Turn/Rebuke Undead: The cleric must present her holy symbol to do this. For each undead Close to the cleric, compare clvl to undead HD:

An evil cleric can control a total of undead HD <= her clvl. A cleric can turn up to (1 + MIND) times between periods of significant rest.


[Coming soon].


BAB: +1 each clvl (so at 1,2,3,4,5,6,7...)
HP: +5 each clvl
Skill bonus:: +3 Physical
Armor/Shield: Any.
Ability: Extra Attacks: For every 5 fighter levels (clvl), a fighter gets an additional attack, albeit at a cumulative -5 penalty. For example, at clvl 10, a fighter can made 3 attacks at +10/+5/+0 base attack bonus.
Ability: Weapon Specialization: At every even fighter clvl, choose a specific weapon type, such as longsword, shortbow, unarmed strike, heavy mace, etc. You deal +1 dmg when attacking with that type of weapon. At subsequent even clvls, you may choose a different weapon type or gain additional +1 bonuses to a type you previously selected.


BAB: +1 each even clvl (so at 2,4,6,8,10...)
HP: +3 each clvl
Skill bonus: +3 Knowledge
Armor/Shield: None. (However, if multiclassed, may use Padded armor and Bucklers without penalty.)
Ability: Arcane spellcasting from the Mage spell list (see Magic).


BAB: +3 every 4 clvls (so +1 at clvls 2,3,4,6,7,8,10...)
HP: +4 each clvl
Skill bonus: +3 Subterfuge. Also, rogues get 3 skill ranks (instead of 2) to spend each clvl.
Armor/Shield: up to Light armor; bucklers only.
Ability: Sneak Attack: Whenever a foe is flat-footed, a rogue may add 2*clvl to damage dealt with melee weapons or ranged weapons at Half-Close range. Does not apply to creatures immune to critical hits and is not doubled on a critical hit.
Ability: Evasion: +1 to Reflex at every even clvl.

While a character uses a prohibited armor or shield (heavier than allowed by that class), she loses her class Abilities.

Multiclassing: The character loses a +1 from an existing class skill bonus to gain only a +1 in the skill bonus offered by the new class. (Thus, all characters get only a total of +3 bonuses to skills.) Otherwise, gain all benefits and restrictions of the new class for the new level.

For now, most other character archetypes can be achieved through multiclassing: bard (Rog + Mag + Clr), paladin (Clr + Ftr), ranger (Ftr + Drd).


There are just 4 skills:

Each level gives you 2 ranks to divide between the 4 skills. You may not have more ranks in a single skill than your level.

Skill roll = d20 + skill rank + any bonus due to your class or race + whatever stat modifier is most applicable to the use + situation modifiers. Roll needs to be >= the given Difficulty Class to succeed.

For example, Climbing would use Phys+STR. Balancing on a narrow beam is Phys+DEX. Finding a trap is Subt+MIND. Disabling a trap is Subt+DEX. Generally, determine skill first and then the relevant stat. More examples:

STR Climbing, jumping, swimming. Quietly breaking a window or forcing a door. Heavy applied skills, such as construction or blacksmithing. Physical intimidation, controlling a half-broken horse.
DEX Acrobatics, balancing, catfalls, climbing, slipping free. Lockpicking, disabling devices, hiding, sneaking. Crafting, building traps, applied skills, first aid. Performing, riding, sleight of hand tricks.
MIND Concentrating, ignoring pain, body control, wilderness survival. Appraising, disguise, forgery, searching. Deciphering texts, diagnosing, knowledge, lore. Bluffing, diplomacy, gathering gossip, sensing motives.

For passive sense checks (such as d20's Spot or Listen), use unmodified Subterfuge.

Saves includes Fortitude (Level/2+STR), Reflex (Level/2+DEX), and Will (Level/2+MIND). Round up.


Within the bounds of the rules, the cosmetic details of weapons, armor, and most gear can be customized/tweaked by the player.


Encumbrance is measured in encumbrance points (encs). 1 enc ~= 5 lbs. Items less than 0.5 enc are of negligible weight; carrying ~10 such items = 0.5 enc.

An Encumbering Load is based on Strength:
Strength is...Encumbering Load (in encs)
< 10 Strength
10 - 15 10 + 2 * (Strength - 10)
15 - 20 20 + 4 * (Strength - 15)
20 - 25 40 + 8 * (Strength - 20)
25 - 30 80 + 16 * (Strength - 25)

If you carry more than your Encumbering Load, you are encumbered: movement is impeded and -dex for each extra 25% (or part thereof) over your Encumbering Load, up to -4 dex at +100% Encumbering Load (Max Load).

If you ever carry more than your Max Load (2 x Encumbering Load), you become flat-footed, cannot make attacks, and cannot move normally but only shuffle a couple steps per turn. (This is in addition to the -4 dex for exceeding your Encumbering Load.) You can lift your Max Load over your head, and lift 2x your Max Load off the ground. You can drag up to 5x your Max Load, depending on conditions.


Weapons deal damage based on category (which generally correlates with weapon size, though this damage is modified according to the appropriate wielder's size):

Damage variation: When damage is rolled, roll dF to determine whether the damage is modified by +variation, -variation, or unaffected. Damage is written as damage±variation. For example, a longsword might do 4±1, meaning it has an equal chance of doing 3, 4, or 5 points of damage each hit.

[Conversion from d20: number of dice = variation, and usually 1/2 of die size + modifier = damage. So a +1 flaming longsword (1d8+1+1d6) would do 8±2 (damage = 4+1+3=8, and there are 2 dice involved meaning a variation of 2). Of course, you may want to keep the fire damage separate, so then 5±1 + 3±1. In this case, a single dF roll can be used to affect both ± entries. (The HTML entry for ± is &plusmn;. Otherwise, a # can be substituted.)]

The default variation increment is 1. This can be customized up to damage - 1. So three different one-handed weapons might do 4±1, 4±2, and 4±3, respectively.

Ranges for weapons and spells are as follows:

Thrown weapons: Some ranged weapons must be thrown. Also, some "throwable" melee weapons can also be thrown without penalty; for such an aerodynamic weapon, decrease its damage by 1 (regardless of how it is used). Thrown weapons can accurately hit anything up to Half-Close, or anything up to Close at -2.

Projectile weapons (slings, bows, crossbows, etc) can hit anything within Close range without penalty, up to Double-Close at -2, and up to Far at -4. Generally, ranged weapons take a round to reload and their dmg is not affected by any STR bonus. An exception is bows (Light or One-handed weapons), which do not need to be reloaded but do suffer any penalty (but not bonus) to STR (as per off-hand weapons). Sufficient ammunition weighs 1 enc if the weapon is your primary weapon or 0.5 enc if you use the weapon only occasionally.

Masterwork: Weapons of masterwork quality cost +300gp and offer +1 to attack rolls. Masterwork throwable melee weapons can instead deal +1 dmg (thus dealing normal dmg for a melee weapon of that type). Only masterwork weapons can be crafted into magic arms; the masterwork +1 to attack does not stack with any magical enchantment bonus.


Armor comes in these categories (though additional intermediate categories may be allowed by the GM):

Shields come in these categories:

Lose shield's AC until next turn after a bash. Spikes can add 1 dmg to shield bashes at cost of 1 enc.

Masterwork: Armor and shields of masterwork quality cost +150gp. Such items are so balanced and well-fitted that they impose 0.5 less enc than normal while worn. However, masterwork armor must be resized for each individual to gain this bonus (Know+DEX, DC25). Only masterwork armor can be crafted into magic armor.


Initial Gear: Unless otherwise noted, all adventurers are assumed to have a standard pack and a couple belt pouches (to keep items like potions, etc. handy). The standard pack includes a bedroll, waterskin (enough for a day), iron rations (for 4 days), a cloak, a partial change of clothes (such as a spare shirt and dry socks), flint and steel, basic mess kit, bandages, one flask of oil, a stout stick (for making a torch), a few bits of thin rope, and a small tarp/raincover.

In addition, there is a 80% chance that, when needed, the standard pack contains any common mundane item that costs 1gp or less, weighs less than 0.5 enc, and is the size of a fist or smaller. Examples include fishing line, candles, a piece of paper, an empty flask, an empty sack, a signal whistle, chalk, soap, sewing needle, whetstone, etc.

In addition, a standard pack has a 20% chance of containing a needed mundane item of up to 1 enc and <= 10gp. Examples include: 50' of rope, a grappling hook, a shovel, a sledge, a steel mirror, an extra day of rations, a crowbar, a collapsing 10' pole, a lantern, etc.

The standard pack weighs 3 enc.

Characters also start with any necessary class equipment--holy symbol (cleric), spellbook (mage), thieves tools (rogue)--usually within handy reach. Characters also have enough spare change for food and basic inn accommodations. This equipment is of negligible enc.

Lvl 1 characters may choose any mundane armor up to Medium armor and Light shield. They also get any 2 mundane weapons of their choice.

Worn items: Each person has a limited number of body slots (with example items): head (hat, headband), face/eyes (goggles), neck (amulet, brooch), torso (under armor: shirt), shoulders (over armor: cloak), waist (belt), forearms (bracelets, bracers), hands (gloves), feet (boots). In addition, a character can wear up to 2 magic rings and 1 set of armor or robes. Except for armor, all weight of such worn items is negligible (though not when carried).

A character can also carry an item in either hand (though not magically use it unless it is designed to be used in hand).



Hit Points = STR + HPs from class levels (with double HP for first level). If HPs reach 0, you fall unconscious and are near death. Further dmg damages Strength instead. If that reaches 0, you die.

Some effects will temporarily change your max HP total. Adjust your current HP by the same amount (as if by healing or taking damage). Therefore, you can take Strength dmg or even die when losing HPs this way.

Other effects offer temporary HPs. Track these separately from your normal HPs. Damage reduces temporary HPs before normal HPs. When the effect ends, you lose any remaining temporary HPs, but your normal HP total is not affected. Multiple effects that grant temporay HPs do not stack but overlap; therefore, each new effect only "refreshes" your current temporary HP total up to the max number offered by that effect. When a temporary HP effect ends, you retain your current temporary HPs if you still have another ongoing effect that also grants temporary HPs. Temp HP cannot be healed or restored once lost.

Healing: HPs heal at lvl per day or night (~12 hours) of bed rest. Each Stat heals at 1 per day or night (~12 hours) of bed rest.


Add attack bonus to d20 roll. If >= your opponent's Armor Class (AC), it's a hit. A natural 20 always hits; if it would have hit anyway, it becomes a critical hit dealing double damage (roll damage twice). A natural 1 always misses.

Fighters and Rogues may use BAB+DEX as their Melee attack bonus instead if wielding a light weapon.

If Fighters and Rogues wield two Light (or smaller) weapon, they can attack with both in a round if they take a -2 penalty on all attack rolls that round.

Damage: Add STR bonus to damage done with your primary-hand melee weapon. Add 2 x STR for 2-handed melee weapons. Any offhand weapon does not get any +STR, but does suffer any -STR. A successful hit always does at least 1 point of dmg.

Armor Class (AC) = (10 + size) + (natural armor + armor + shield) + deflection + DEX + misc. Misc AC can come from combat modifiers (such as cover or being prone) or various conditions (such as being unguarded or helpless). Touch attacks ignore natural armor, armor, and shield AC.

Turn sequence: Roll Reflexes for initiative order. If a surprise round, only aware characters get to act while the rest are flat-footed and dazed.


1 turn = 1 full action or 1 std action + 1 minor action or 2 minor actions. May also get 1 or more free actions (as is reasonable).

Examples of action length:

Special Combat Actions

Aid (std): If you and an ally are in melee combat with the same target, attack vs AC10 to give +2 to either ally's attack or ally's AC against that target.

Aim (minor): +2 to next your attack if made this turn. If against an adjacent, immobile object you automatically hit; if that object is a helpless creature, your attack becomes a coup de grace. Aiming leaves you flat-footed until your next turn (as per Charge).

Attack an object (attack): If the object is held or worn by a character, that character gets a chance to avoid your blow: use the sunder manuever. Otherwise, immobile inanimate objects are like helpless creatures: 5 AC (modified by size) with no DEX modifier. Sample size modifiers include: +1 (small) for two-handed weapons; +2 (tiny) for one-handed; +4 (dimin) for light weapons and scrolls; +8 (fine) for potion vials. [Hardness = DR]

Block (std or full): Give up your attacks in order to block attacks later this round with an appropriate weapon or shield. Contest each attack you wish to block with a melee attack roll; if successful, you deflect the blow; otherwise, you must rely on your AC to protect you as normal. If made as a std action, you can block only one attack this round; if a full action, you can make as many blocks (at the same penalties) as you would attacks in a turn.

Combat trick (std): Use an appropriate skill contest to gain an advantage in melee combat. Both you and your target get to add their BAB to their skill rolls. This action might represent a trick, a combat style, or using the environment to your advantage. Examples including: tumbling or leaping around your opponent, forcing an opponent off-balance on a treacherous surface, appraising the target's combat style for weaknesses, feinting/distracting, demoralizing/intimidating the opponent, etc. Sample effects include making the target flat-footed, shaken, dazed, or gaining or granting an ally a +2 on a single attack against that target. The effect gained should be appropriate to the trick. Effects last only a single round. You may take -4 to the skill roll to do this as a minor action. If you fail the contest by 10 or more, you may suffer some equivalent, relevant mishap instead.

Charge (full): You can move up to to your full action distance (usually Close) in a turn and still make a single attack. This leaves you flat-footed until your next turn.

Delay (minor): Wait until later in this round to use a std action. If you just wait, you can choose to act after any character's action. If you ready instead, you specify the area or character you are watching and the specific event that you intend to interrupt, meaning you get to act just before that event. (If a character suspects you are ready for them, they may try to beat you to the drop: contest Reflexes to see who gets to go first.) If your turn comes around again and you still haven't acted, you lose your std action.

Dodge (full): Give up all attacks for +4 dodge AC until your next turn. Alternately, make only a single attack at -4 to gain +2 dodge AC until your next turn.

Maneuver (attack): Instead dealing damage, these special attacks instead produce an effect but are resisted by the target. Make a melee touch attack using either STR or DEX as seems appropriate. If successful, the target can then resist the effect with a melee attack roll (again, using STR or DEX as seems appropriate). Failing the contest by 10 or more may have an ill effect for the attacker (such as being tripped or knocked back in return). Example manevers include:

Move (varies): If your speed is normal, you can move a Half-Close distance as a minor action or Close as a full action. If you run, you can get to Double-Close, but this leaves you flat-footed until your next turn. If you are impeded, half these distances. If you do not otherwise move during your turn, you can move a couple steps as a free action at any point during your turn.

Combat Modifiers

GM's friend: +2 or -2 for advantageous or disadvantageous circumstances, or maybe +4/-4 if particularly notable.

Otherwise, more specifically:


Mages can cast any arcane spell with a spell level (slvl) equal or below 1/2 their caster level (clvl), rounded up. Mages have access to all spells in the arcane spell list. Clerics work the same, only with divine (instead of arcane) spells.

Casters have a max slvl = Mind - 10. They can never cast spells of a slvl higher than this.

Spell Points: Casting a spell of any kind costs Spell Points (SP). A spellcaster has a pool of SP equal to ((6 + STR + MIND) * clvl)/2, rounded down.

A spell's SP cost is 1 + double the level of the spell being cast:

Spell Level:  0  1  2  3  4  5  6  7  8  9
SP Cost:      1  3  5  7  9 11 13 15 17 19

SPs can only be recovered by a period of significant, uninterrupted rest (usually 2 hours), after which all SP are restored.

There is no need to memorize spells in advance. However, just because a character can cast any spell doesn't mean that they should. Choose spells that suit the character. Each clvl, choose a "signature" spell of any slvl that you can cast at that clvl. Signature spells cost 1 less SP to cast (meaning that a signature 0-slvl can be cast for free).

Specialization: If the first signature spell chosen at each new slvl is from a single school (for mages) or a single d20 domain list (for clerics), the caster may choose one of the following benefits whenever casting those signature spells: +1 save DC; +1 effective clvl; +1 slvl for free when applying metamagic. If all signatures spells are from a single school (for mages) or from two d20 domains lists (for clerics), double these benefits for all signature spells.

Magic Attack bonus (see to-hit) is used to make any magic-based attack, such as a spell touch attack or ray.

The save DC for all spells is 10 + clvl/2 + MIND, rounded up.


Regarding spells in general:

Metamagic. For an increase in spell level, spells can usually be customized (subject to GM approval). The caster must still be able to cast a spell of the increased slvl:

Ceremonies: Not all magic comes in the form of spells; these are simply the well-known, easily-replicated magical effects of the world. Special magical rituals called ceremonies may also produce potent magical effects. However, ceremonies are generally require some combination of prior research, detailed preparation, a specific time or place, rare material components, multiple coordinating casters, certain prerequiste spells, etc. Becoming a lich, constructing a golem, crafting artifacts and intelligent items, summoning a demon legion, and poisoning a town's entire water supply are all examples of this.


GM Content

GM Toolbox

Things to Remember

Optional Rules

Heroic Exertions

Once per encounter, a PC can exert herself to change the effects of a die roll by one degree of success in either direction--for example, change a failure to a success, a critical failure (natural 1) to a regular failure, or a critical hit (natural 20) to just a regular hit. This can be applied to any roll the PC makes or oppenent's roll when in a contest with the PC (AC counts as contesting an attack). So a PC could make their attack successful, but also turn an oppenent's successful attack or save into a miss or failure.

Each exertion causes 1 dmg to the most relevant stat (DEX for AC) and grants the GM one karma point.

The GM starts the game with one karma point. A GM can spend a karma point to grant any NPC an heroic exertion or to negate the effects of a PC's exertion, allowing the dice to determine the effect after all (the PC still suffers the stat damage for a negate exertion). (The GM may also allow other benefits or uses for exertions and karma points.)

This rule grants a bit more cinematic flavor and stability to PCs, though limited to only once per encounter. Yet, each exertion simply gives GMs an equivalent amount of power to use later--which can be especially handy for GMs that like to roll in the open.

d20 PCs

This is a good option if you either want more detailed PCs or if you just want to try z20 without converting your PCs just yet. PCs can be completely d20 (even using d20 damage rules) or some blend of d20 and z20. When blending:

If using d20's abilities (stats) with z20 skills:
  • z20 STR: Use d20 CON for determining HPs and Fort save and d20 STR for everything else.
  • z20 DEX: Use d20 DEX.
  • z20 MIND: Use d20 CHA with Comm and Cleric's Turning Undead, d20 INT with Know and Subt, and d20 WIS for everything else. Spellcasters should use the appropriate d20 stat when determining their max slvl and SP pool.
str mods effect both STR and CON; mind mods effect INT, WIS, and CHA equally.

Since there are now twice the number of stats, gain a +1 to a stat every 2nd level (if not using feats). You may not add more than +5 to a single stat through the course of such progression.

Some minor adjustments may be required,. For example, certain combat maneuver feats don't offer protection from AoOs, but still grant +4 to certain kinds of attacks. Mobility might instead grant a +grade to movement speed. And so forth.

If using z20 magic:
  • Item Creation: As z20, but raw material costs are increased by 20% for those without the requisite feats.
  • Metamagic: For those with a feat, +slvl still required, but at a cost of only 1 SP (rather than 2) per extra slvl.
Can be d20 spell-preparation, but with z20 spells. If z20 SP-based, Paladins and Rangers get only 1/2 normal SP totals.

Combat, adventuring rules, spells, monster, and NPCs should all follow z20 rules.


Catching Fire

If exposed to non-instantaneous fire for a full turn or more, Reflex (DC15). On failure, catch on fire. While on fire, make a Reflex save at that start of each of your turns (+4 if you spend the turn to drop and roll) to put the fire out. On failure, take 3±1 dmg.

Damaging Liquids

Examples include acid, boiling water, holy water on undead, hot oil or tar, water on a fire-based creature, etc. Make a ranged attack as for a thrown weapon. Deals 3±1 dmg, and 1 dmg of splash to any creature next to it. Immersion deals 30±10. May have special effects (such as potentially catching on fire for alchemist's fire or Molotov cocktail).

Variations: Particularly dangerous liquids--lava or molten metal--or additional quanities--bucketfull (-2 attack)--do double damage. Being caught in a downpour (waterfall, emptied cauldron) might do 15±5 dmg, Reflex for 1/2.

Depravation & Exposure

This covers extreme temperatures, suffocation (such as drowning or smoke inhalation), starvation, thirst, etc. The more extreme the situation, the more often a save is made: once per day/hour/10 minutes/minute/round. (Suvival skills--Phys+STR--might shape the situation to be less extreme.) Characters may receive a certain grace period before checks need to be made.

Fort save vs DC15 + 1 per previous check. Inappropriate attire, etc may grant +/- 2 or 4.

On failure, take -str (and -dex for cold). If str debilitated, take 3±1 dmg instead. Penalties are removed when the character is no longer deprived (though may take a small amount of recovery time).

For example, if trapped underwater after a deep breath, a character might hold his breath up to STR minutes, then must check every round. On the other hand, if the character is swimming, fighting, or out-of-breath, he only gets STR rounds before checking every round. If weighed down by armor, -2; if actually encumbered with gear, -4.



Deals 3±1 dmg per 10' fallen. Intentionally jumping down reduces fall by 10'; a skillful landing (Phys+DEX; DC15) can reduce the fall by (another) 10'.


Characters start knowing their racial language (if any) and Common. They may know one additional language per +MIND. Characters with -MIND are illiterate. Additional languages and literacy may be learned through play.


Light conditions can be bright (enough to see clearly), shadowy (20% miss chance), or darkness (blinded). Most lights fill the Half-Close range with bright light, and out to Close with shadowy light. Characters with Lowlight vision double these ranges (to Close and Double-Close); they can also see normally in lighting that is only shadowy (such as by moonlight or starlight). Those with Darkvision can see at least as far as Close in any non-magical lighting conditions, though only in black and white while in darkness.



Shaken: -2 mind as fear clouds your thoughts. May need a Will save (DC of original effect) to be able to approach the object of your fear.
Frightened: As shaken, but you also flee the source of your fear. (Make a Will save each turn to stop running.) If there is no open avenue of escape, you can stand and fight.
Panicked: As frightened, but drop everything and flee. If you cannot flee, cower.
These effects are cumulative. That is, if you become shaken when already shaken, you become frightened instead.
Unable to see. The makes certain visual actions (such as spotting enemies, reading, or being affected by gaze attacks) impossible, though others actions that simply benefit from sight (such as searching a chest for a particular item or reacting quickly to the presence of foes) might just be much harder (-4) and take longer. In combat, blinded characters are unguarded, impeded, and all foes have full concealment (must guess/determine their location and then still suffer a 50% miss chance). Characters who remain blinded for a long time grow accustomed to these drawbacks and can overcome some of them.
Unable to take proactive actions (even purely mental ones), but can still defend yourself normally. You might be fascinated, hypnotized, sleepy, or otherwise inattentive: -4 to notice your surroundings, though an obvious threat will break the effect. You might be cowering in fear or stunned: treat as also unguarded.
Visually over-stimulated, as by bright light: all your attacks suffer a 10% miss chance. (See also blinded.)
Cannot hear. This also means -4 to reflex/initiative checks at the start of combat and a 20% chance of losing a spell with a verbal component (which is every spell except those cast with the Silent metamagic options). Characters who remain deafened for a long time grow accustomed to these drawbacks and can overcome some of them.
If any STAT is reduced to -6 or lower by a combination of mods, you are debilitated. The effect depends on the particular stat: unconscious (STR or MIND) or paralyzed (DEX).
energy drained
Suffering one or more negative levels. See energy drain.
-2 dex, impeded (and possibly anchored to the current location, depending on the effect). Spellcasters suffer a 20% chance of losing a spell with a somatic/gesture component (which is every spell except those cast with the Still metamagic options). (See also: grappled and encumbered.)
Tired and worn you, you suffer a -all and can not run or charge. It takes a full night's (or day's) to remove fatigue. Doing anything that would normally cause fatigue causes you to become exhausted: -2 all and impeded, which stacks with the effects of being fatigued. A significant rest reduces exhaustion to fatigue.
Surprised, flanked, over-burdened, or otherwise unable to actively defend yourself: lose any positive DEX bonus (and any other dodge bonuses) to AC. This may also have other effects, such as being open to rogue sneak attacks. (Unlike d20, losing your DEX bonus and being flat-footed are always the same thing in z20.)
Driven to mindlessly flee, you can take no actions other than move. This is normally an affect of fear, but can also occur when nauseated (in which case, your speed is also impeded). (See also: dazed)
Completely unable to move. If you are not also unconscious, you are aware of your surroundings and can take purely mental actions. You might be bound, held, paralyzed, or pinned. Such immobile characters are flat-footed and suffer -5 AC. Also, if an adjacent opponent spends a turn to aim a single coup-de-grace attack, they automatically hit and do double (critical) damage; the victim must then Fort save (DC10+dmg) or die.
Your movement speed is reduced by one category. You can be impeded by terrain, being entangled, slowed, or other conditions. If you become impeded by multiple effects, your speed decreases each time.
stat damaged
You are suffering one or more points of dmg to a stat. See stat damage for effects and healing for healing rates. If the damage is permanent (until healed magically), you are stat drained.
Your defense is actually impaired: as flat-footed (lose +DEX to AC) and also suffer -2 AC.
Unware of your surroundings, helpless, and usually prone. If only asleep, you can be roused by damage, a good shake, or (if the sleep is not magical) a loud noise. Otherwise, you do not regain consciousness until the effect ends (such as by healing or resting sufficiently, etc.). May also be petrified or debilitated.

Magic Items

To craft an item, the crafter must:

Items that store spells are either arcane or divine, generally usable only by weilders of the same type of magic. Items that are priced in terms of slvl * clvl must be crafted at a clvl sufficient to cast a spell of that slvl. New items must be constructed fully charged, but may be recharged later for a price equivalent to the number of added charges.


A scroll costs slvl * clvl * 25gp. A spell-completion item.

Scrolls need not be a paper scroll, but simply any written form that can only be deciphered and understood by someone with the spell on their spell list: a spellbook page, a gem with tiny glyphs inside, a painted runestone, etc. Any caster that has deciphered the scroll and has the spell on his spell list can cast the stored spell (at its stored clvl) without personal SP cost.

If clvl of the scroll is greater than user's clvl, make a Spellcraft check DC 10+scroll's clvl to not lose the spell when cast. On a natural 1, something bad happens. (Default: 3±1 dmg per slvl to spellcaster.)


Potions cost slvl * clvl * 50gp. Max slvl: 3. A use-activated item.

A potion can be any item whose destruction could release a spell: a wafer, an oil, a slip-knotted string, a fragile crystal, etc. Anyone can use a potion. Upon use, the stored spell affects the user as its target.


Wands cost slvl * clvl * 750gp. They have 50 charges of a single spell when constructed. A spell-trigger item.

Wands too can come in a variety of forms. As a traditional wand, it is wielded like a light weapon, but it is generally too delicate to deal damage. A character must have the wand's spell on his class list to use it.


Staffs provide raw SP to casters to power their own spells. Each staff has a clvl, which cannot be higher than its creator's. Each charge of a staff costs clvl * 30gp. When constructed, it must have at least 50 charges (so 1500gp * clvl). A spell-point storage item.

A user can then use 1 charge per slvl to cast any spell he knows. (slvl 0 counts as 1.) All SP costs for the spell must come from the staff in this way; the user cannot supplement that staff from his own SP pool. All spells cast using the staff are cast at its clvl. If this is higher than the user's clvl, a check must be made (as per a scoll) to control each spell.

A staff is wielded like a two-handed weapon; -1 enc if it is too delicate to deal damage. Occassionally, "staffs" come in other forms, such as a crystal ball, wand, glass eye, gem amulet, etc.

Weapons and Armor

As expected per d20. Magical ranged weapons imbue their ammo with magic when fired. Magic ammunition effectively imbues the ranged weapon with the given bonus while firing that single shot.

Wonderous Items

Also includes rods and rings.

PC Wealth

Since PCs level up whenever you think they're ready, it's handy to know how much treasure you should have handed out at each point. Character should have roughly this value in gear at the start of each level:

1[mundane only]613,000gp1166,000gp16260,000gp

Be wary of handing out items worth more than 30% of a character's total wealth.


The first rule of monsters: monsters don't follow the same rules as PCs. Instead, they are copied (loosely) from d20 sources.

Monster Abilities

Monster abilities are either:

Movement Modes (Na)

The first aspect of momement is the speed at which it occurs:

Most of these speed categories can be subdivided into 3 grades, giving a + or - version (like grades). In combat, these are equivalent, but over long distances, a higher grade will eventually catch up with a lower grade.

Movement may also be a different mode than walking/running, such as: burrowing, climbing, flying(wings), flying(perfect), and swim. If a creature has a different mode, it can move in that way as easily as humans walk or run (no checks required), though it may still experience certain terrain handicaps. Flying(perfect) means the creature can hover or move vertically or backwards at will (like a hummingbird or will-o-wisp). Flying(wings) operates like winged flight: the creature must spend a minor action each turn to flap its wings, either to move forward or to hover (though hovering may be of limited duration, as per holding breath); it may be able to glide for free for a turn or two, though.

Blindsense (Ex)
Can locate creatures, but cannot pinpoint them: knows their location, but still suffers the normal 50% miss chance, as well as the impeded and unguarded ramifications of being blinded.
Blindsight (Ex)
Can pinpoint the location of creatures and objects using a non-visual sense (such as echolocation, keen hearing or scent, vibrations, etc), and so suffers no penalties for not being able to see.
Scent (Ex)
Can detect Close creatures, and then spend a turn to determine direction or track a trail; can only determine their exact location within 5'. Wind, precipation, other smells, strength of smell, etc. may affect any DCs.
Tremorsense (Ex)
As Blindsight, can pinpoint the location of any creature touching the ground and moving (such as casting spells or fighting).
Special Qualities
Damage Resistance
Fast Healing
Energy Resistance/ Immunity / Vulnerability
Spell Resistance / Immunity
Turn Resistance (Ex)
Add this amount to an undead's HD when determining the effect of being turned, rebuked, etc.
Attack Modes
Breath Weapon (Su)
Usually produces a Half-Close Cone (for Medium or smaller creatures) or Close Cone (for Large or larger). Reflex save for 1/2 dmg. Creatures are immune to their own breath weapon.
Constrict (Ex)
Can automatically deal this bludgeoning damage each turn to an already-grappled foe.
Gaze (Su)
Improved Grab (Ex)
Can start a grapple with either a regular melee attack (which also deals normal damage) or a touch attack (which does not). The victim does not get a chance to defend/contest the initial grapple (though may attempt to escape it later on their turn and can still contest pins, as normal).
Natural Weapons (Na)
Includes (dealing Peircing, Slashing, or Bludgeoning damage) : bite (Pr/Sl/Bl; 3 dmg), claw or talon (P/S; 2 dmg), gore (Pr; 3 dmg), slam or tail slap (Bl; 2/3 dmg), sting (Pr; 2 dmg), or tentacle (Bl; 2 dmg). (Dmg is average/approximate for a Medium-sized creature and can vary by monster.)
Pounce (Ex)
Do not suffer any negative effects from charging.
Powerful Charge (Ex)
Deals this extra damage when charging.
Rake (Ex)
A more powerful attack usable only against an already-grappled a foe. You can also use it again a foe grappling you (successful grapple contest required).
Swallow Whole (Ex)
Swallow a smaller creature already grappled in the mouth: treat as going for a pin (victim gets to contest this even if the swallower has Improved Grab). The swallowed creature is still considered to be grappled (but not pinned); the swallower is no longer grappling. A swallowed creature can try to cut its way free with any light slashing or piercing weapon (AC of insides = 10 + 1/2 nat armor, with no size or DEX bonus) or it can try to escape the grapple to crawl back up into the mouth.
Trample (Ex)
Deal this bludgeoning damage by moving over characters smaller than themselves. Victims can make a Reflex save for 1/2 dmg.
Attack Effects
Death Attack
Save or die (as if reduced to 0 HP and 0 Strength).
Disease (Ex)
See Disease
Energy Drain (Su)
Poison (Ex)
See Poison
Stat score loss (Su)
Special Abilities
Change Shape (Su)
You superficially assume the physical appearance of another form, meaning you are largely still your old self in a new body. Follow the rules for Polymorph, with the following exceptions:
Charm / Compulsion
Fear / Frightful Presence
Polymorph (Su)
You truly assume a new physical form that feels comfortable and natural, but you retain your mind.
Transformation (Su)
A greater form of polymorph, you truly become another creature.

Monster Types and Subtypes

An aberration has a bizarre anatomy, strange abilities, an alien mindset, or any combination of the three. Darkvision. Aberrations eat, sleep, and breathe.
Counts as aquatic, but can breath air.
Lives in the water, has a swim speed, can breathe underwater, can't breath air (unless amphibious).
A giant is a humanoid-shaped creature of great strength, usually of at least Large size. Low-light vision. Giants eat, sleep, and breathe.
Stealthy humanoids who live by hunting and raiding and who all speak Goblin.
Humanoids breathe, eat, and sleep.



About z20

Author: Zach Tomaszewski (zach @ snarkdreams.com)

z20 is a stripped-down version of d20, built upon Microlite20 and incorporating a few d20house rules and other ideas picked up here and there. It aims to achieve at least 80% of the flavor of d20--hit points, leveling up, dungeon-crawling, gold-driven magic items, ability to fight unhindered until you drop, d20 spells and monsters--with only about 20% of the rules. Furthermore, z20 is meant to be similar enough to d20 that conversion of material can largely be done on the fly (when necessary).

(If you're looking instead for an even liter version of Microlite20, check out M20 Hard Core; for more of an old-school flavor, see Microlite74.)

Sample Simplifications from Microlite20 and d20
Sample Expansions from Microlite20

Some other good ideas pilfered from:


0.92 - Alpha release. (12 May 2010) [Current Version]
Core not quite done and still a little rough around around the edges. However, no further development is planned.
0.90 - Initial posting. (06 Aug 2009)

Glossary of Abbreviations

Base Attack Bonus, which is the total of the BAB granted by all your clvls.
Class level or, more specifically regarding spells, caster level. Refers to the number of levels a character has in (only) the relevant class.
A Fudge die, which has six sides: 2 +s, 2 blanks/0s, and 2 -s.
Physical damage, which reduce HPs an equivalent amount. See Weapons and Combat.
The total number of levels a character has in all classes.
Spell level, which is 0 through 9.
Either Strength, Dexterity, or Mind. Usually spelled out and written with an initial capital letter. See Stats.
stat mod
A temporary modifier related to a particular stat, but of more limited scope than the related stat modifier. These are used as an alternative to modifying a stat or stat modifier directly, thereby avoiding the need to recalculate a number of character traits during gametime. Stat mods include: str, dex, mind, all, and saves (written in all lowercase).
stat modifier
The bonus (positive) or penalty (negative) granted by a particular stat. (Not to be confused with teh more limited stat mod.) See Stats for more, including the stat modifier formula. Stat modifiers are designated as either STR, DEX, or MIND (written in all uppercase).


z20 is Product Identity; everything else is Open Game Content.


The following text is the property of Wizards of the Coast, Inc. and is Copyright 2000 Wizards of the Coast, Inc ("Wizards"). All Rights Reserved.

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2. The License: This License applies to any Open Game Content that contains a notice indicating that the Open Game Content may only be Used under and in terms of this License. You must affix such a notice to any Open Game Content that you Use. No terms may be added to or subtracted from this License except as described by the License itself. No other terms or conditions may be applied to any Open Game Content distributed using this License.

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Open Game License v 1.0 Copyright 2000, Wizards of the Coast, Inc.

System Reference Document. Copyright 2000-2003, Wizards of the Coast, Inc.; Authors: Jonathan Tweet, Monte Cook, Skip Williams, Rich baker, Andy Collins, David Noonan, Rich Redman, Bruce R. Cordell, based on original material by E. Gary Gygax and Dave Arneson.

Unearthed Arcana. Copyright 2004, Wizards of the Coast, Inc.; Authors: Andy Collins, Jesse Decker, David Noonan, Rich Redman.

System Reference Document v3.5 HTML compilation. Copyright 2007, Sovelior Meliamne & Jason Olaf Jensen.

Microlite20. Copyright 2006, Robin V. Stacey (robin@greywulf.net).

z20. Copyright 2009, Zach Tomaszewski.