Roll Checks

This page defines how Ninefold builds a chance to pass (toPass), converts that chance to dice, resolves sequential contested rolls, measures outcome margins, and applies critical bands. See Stats for the meaning of each stat and Stat Generation for starting values.

Check Sequence

Resolve every uncertain action in this order:

1. Declare the action, target, relevant stat, applicable trained skill path, and any buffs or debuffs.
2. Calculate the action's final toPass percentage.
3. Choose a die that can express that percentage and roll the check.
4. If the action is opposed, the defender then calculates and rolls its own toPass check.
5. If the action gets through the required checks, roll its effect, such as damage.

An ordinary check stops after step 3. A contested or combat action normally uses an offensive check followed by a defensive check; these are two separate rolls, not one subtraction or opposed-total roll. The effect is rolled only after the required checks let it through.

Roll Checks

The Difficulty Class is the chance to pass.

DC = toPass

toPass = Stat + Skills + Buff Bonus - Debuff Bonus

New Minds generate starting Mentalic Stats from +4% to +24% by rolling 4d6 for each one. Other Stats may still be supplied by an Embodiment or changed by the rules; use the recorded value without clamping it.

Combined range before debuffs: -75% to +75%. Debuffs may modify that by a further -50% to +50%.

Dice Thresholds

d6, 3+ = toPass 50%

d20, 16+ = toPass 40%

dN, X+ = toPass (N - X) / N %

Dice Threshold Table

Skill Checks

Ordinary skill checks, attack checks, and defense checks all use the same formula:

toPass = Stat + Skills + Buff Bonus - Debuff Bonus

Choose the relevant Stat and the applicable trained Skill path for the declared action. Add the proficiency bonuses from that one Skill path; unrelated Skill paths do not stack.

Equipment, armour, shields, cover, aspects, conditions, resistances, and armour piercing count as Buff Bonuses or Debuff Bonuses when their rules apply.

There is no universal proficiency bonus. Two characters with the same Stat can have different Skill bonuses.

Embodiment Modifiers

The active Embodiment supplies the relevant physical stat and may improve or impair the check through a relevant bodily feature. For example, poor robotic sensors might impose -2% on Perception checks. The Mind retains its Perception stat and trained proficiency after leaving that body; only the embodiment modifier changes.

Contested and Combat Rolls

Ninefold has no separate saving-throw procedure. Offense and defense are skill checks using the standard toPass formula.

1. Offense: make a skill check using the relevant Stat and weapon or effect Skill. Roll the offensive check. On a failure, stop.
2. Defense: make a skill check using the relevant Stat and armour or evasion Skill. Apply cover, resistances, armour piercing, and other applicable bonuses or penalties. Roll the defensive check. On a success, the defense prevents the hit unless the action states a reduced effect instead.
3. Effect: if the offense passed and the defense failed, roll damage or the action's other effect.

The general effect classes are:

For area hits, N comes from the target's exposed base area. A fully exposed five-foot base is one exposure unit. See Area Effects.

A typed resistance is an additional percentage-point bonus on the defender's roll:

defense toPass = defense stat + defense skill
                 + armor + cover + max(applicable resistance bonuses)
                 + buffs - debuffs - armor piercing

If an effect has several types, use only the highest matching resistance; never add resistance bonuses together. For example, defending against a fire-and-poison effect with fire +20% and poison +35% adds only +35%.

A missing resistance contributes +0%. A negative resistance is a vulnerability and reduces the defense chance. Immunity is an explicit property stating that the effect does not apply, not a numeric resistance.

Percentage DCs and Outcome Margin

When a check uses a fixed percentage difficulty instead of a direct toPass roll:

adjusted result = converted percentile roll + total check bonus
margin = adjusted result - DC

Resolve two independent results from the same roll: compare the adjusted result with the DC for success and effort, then compare the unmodified die result with the critical bands.

These are percentage-point margins, not multipliers. For roll-under presentation, calculate the same margin as final chance - converted roll; the bands remain identical. Critical status is independent, so a check can be both critical and barely passed, or critical and effortless.

Critical Bands

Every check has a default 5% favorable critical band and 5% unfavorable critical band at opposite extremes of the unmodified die.

On d100 these are 01-05 and 96-100. On d20 they are the natural extreme faces, with the favorable face determined by the convention.

On a successful action, a favorable critical doubles effect dice. An unfavorable critical halves effect dice if the action still succeeds, rounding down to at least one die. Critical status never changes success into failure or failure into success. An action without effect dice has no default critical dice change.

Critical-focused builds and equipment change a band in percentage points. Critical +5% widens the favorable band from 5% to 10%; incoming critical -5% can narrow it from 5% to 0%. When the selected die cannot express the final percentage, use d100/d20 or an appropriate confirmation roll.

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