Core Rules

Core rules are the assumptions that the rest of the system is built on. These rules are here so they do not need to be repeated in every ability, spell, feat, or combat entry. If a specific rule says something different than this page, the specific rule wins.

The Definition Master is still the final judge of how a strange interaction works. If two rules produce a result that does not make sense for the table, talk it through and use the ruling that keeps the game moving.

Dice

Most rolls are made with a twenty-sided die. This will usually be written as 1d20. Damage, healing, and other variable effects use the same format. 2d6 means roll two six-sided dice and add them together.

When a rule says to roll something and add a modifier, the formula is usually:

Roll: 1d20 + relevant attribute modifier + skill, attack, save, or other listed modifiers.

If a rule gives a flat value, do not roll unless the rule says to roll.

Rounding

Unless a rule says otherwise, always round down. This matters most for half HD, divided skill bonuses, caster level adjustments, damage dice, and any other formula that can produce a fraction.

If multiple parts of a formula divide or multiply values, finish the full formula before rounding unless the rule tells you to round at a specific step.

Hit Dice and Level

Hit Dice, or HD, is the level of a character or creature. If a rule refers to level, character level, creature level, or HD, use Hit Dice unless the rule clearly means spell level, item level, or some other separate value.

Spells have spell levels. Characters have Hit Dice. These are not the same thing.

Attributes and Modifiers

The six main attributes are Strength, Dexterity, Constitution, Intelligence, Wisdom, and Charisma.

When a rule asks for an attribute modifier, use the modifier from the current attribute score. If attribute damage, magic, afflictions, or other effects change the attribute score, the modifier changes as well.

Temporary changes apply while the effect lasts. Permanent changes apply until removed by another rule.

Primary Mental Attribute

The Primary Mental Attribute, or PMA, is the attribute a caster uses for magic. It will be Intelligence, Wisdom, or Charisma. Once chosen, it does not change unless a rule explicitly allows it.

If a spell, definition, ability, or feat refers to PMA, use the character's current PMA modifier.

Difficulty Checks

Many rules ask for a Difficulty Check, or DC. The character rolls 1d20 and adds the appropriate modifier. If the result is equal to or higher than the DC, the check succeeds.

If two creatures are directly competing, use an opposed roll instead. Both creatures roll the appropriate check, and the higher result wins. If the result is tied, reroll until there is a winner.

Natural Rolls

A natural roll is the number shown on the die before modifiers are added.

By default, a natural 20 on an attack roll is a critical threat. A natural 1 on an attack roll is a miss.

For saves, skills, opposed rolls, and other checks, natural 1s and natural 20s are not automatic failure or automatic success unless a rule says otherwise. The final result after modifiers is what matters.

Critical Hits

When an attack roll lands within the weapon's critical range and would hit the target, it threatens a critical hit. Roll the attack again using the same attack bonus. If the confirmation roll also hits, multiply the damage by the weapon's critical multiplier.

Extra damage dice are not multiplied unless the rule that grants them says they are. Flat weapon damage, Strength damage, enhancement bonuses, and other normal damage bonuses are multiplied.

If a target is immune to critical hits, the attack still hits normally, but the damage is not multiplied.

Bonus Types

Bonuses are named when their source matters. Examples include circumstance, competence, dodge, enhancement, inherent, insight, morale, holy, and unholy bonuses.

Bonuses of the same type do not stack unless a rule says they do. Use the highest bonus of that type.

Bonuses with different types stack with each other. Untyped bonuses stack unless they come from the same named source.

Dodge bonuses stack with other dodge bonuses unless a rule says otherwise.

Penalties usually stack unless they come from the same named source or the Definition Master decides the same penalty is being counted twice.

Stacking Effects

If the same spell, ability, feat, or item affects a creature more than once, use the strongest version unless the rule says the effect stacks.

If two effects give the same condition, use the longer duration. If one effect gives a stronger version of the same problem, use the stronger version.

If two rules both modify the same number in different ways, apply flat bonuses and penalties first, then multipliers.

Minimums

Unless a rule says otherwise, damage cannot be reduced below 0. Healing cannot reduce damage below 0. A penalty cannot make a creature worse than unable to attempt the action unless the rule says it can.

If a rule gives a creature at least one use of something, that minimum is kept even if modifiers would reduce the value to 0 or lower.

Time

Combat is divided into rounds. A round is about 6 seconds.

A turn is one creature's chance to act within the round. Effects that last until the start or end of a creature's turn use that creature's next turn unless the rule says otherwise.

Out of combat, time should be handled in whatever unit fits the scene. Minutes, hours, days, and weeks are all valid if the action being taken makes sense at that scale.

Actions

The common action types are move action, standard action, swift action, free action, immediate action, and full-round action.

If a rule does not list an action type, the Definition Master decides what kind of action is appropriate. Simple things should not take more action than they deserve, but anything that has risk, timing pressure, or direct combat value should usually take an action.

Measurements

Combat uses feet and squares. A normal square is 5 ft. by 5 ft.

When counting distance on a grid, count from one square to another in the way that is most natural for the table. If exact distance matters, the Definition Master decides the final distance.

Ranges, areas, and movement should be handled consistently once a table chooses how diagonals and unusual shapes work.

Size

Most player characters are Small or Medium. Small and Medium characters normally occupy one 5 ft. square.

Size can modify combat maneuvers, reach, carrying, creature space, and other rules. If a size rule is not listed in the specific entry being used, follow the general size guidance in the glossary or the closest matching creature example.

Damage

Damage is subtracted from current HP after reductions, resistances, weaknesses, or other defensive rules are applied.

If multiple damage types are dealt by the same attack, apply the relevant reduction or resistance to the matching damage type. If a rule cannot cleanly separate the damage types, the Definition Master decides which defense applies.

Damage reduction applies to physical damage unless the entry says otherwise. Energy resistance applies to the listed energy type.

Conditions and Afflictions

Conditions are temporary states such as being prone, stunned, fatigued, or concealed. Afflictions are longer-term problems such as curses, injuries, diseases, and genetic issues.

If a condition and an affliction both apply, both are active unless they clearly describe the same problem. If they do describe the same problem, use the stronger effect.

Rule Conflicts

When rules conflict, use this order:

1. The specific rule in the spell, ability, feat, definition, item, or monster entry.
2. The rules for the subsystem being used, such as combat, spell casting, skills, or equipment.
3. These core rules.
4. The Definition Master's ruling.

If an older page and a newer page disagree, use the rule that is more specific and better supported by the surrounding system.

Optional Rules

Optional rules are not assumed to be active. A table should decide before a campaign starts which optional rules are being used.

If an optional rule is added during play, it should not punish a character for choices made before the rule existed unless the whole table agrees to it.