Base Resolution

Philosophy

In Cerberus, the GM judges and the dice decide. There is no skill list, Armor Class, or collection of situational modifiers to memorize. Whenever an action has an uncertain outcome, the GM turns that judgment into a probability. Three types of roll resolve every situation.

Attributes

Every character has six attributes, expressed directly as modifiers: Strength (STR), Dexterity (DEX), Constitution (CON), Intelligence (INT), Wisdom (WIS), and Charisma (CHA). There is no hidden score out of 20 behind them: a Barbarian's +8 Strength is their Strength.

Roll No. 1—The Prescribed Chance Roll

The prescribed chance roll replaces every skill. When a character attempts something with an uncertain outcome, the GM announces a probability based on the character—their attributes, history, and equipment—and the player's proposed plan.

One convention, always from the player's perspective: the GM announces “X chances out of Y.” The player rolls 1dY. On a result of X or lower, the player gets what they wanted.

GM: Climbing that wall at night, with your agility and rope: 4 chances out of 5. Player: (rolls 1d5) I rolled 2. GM: You clear the wall without a sound.

Three golden rules for the GM:

1. Do not roll when the outcome is certain. A master thief picking an ordinary lock succeeds. A peasant trying to jump a 30-foot chasm fails. Roll only when genuine uncertainty exists.
2. The plan matters more than the character sheet. Waiting for the guard shift, creating a diversion, or crossing the roof improves the odds. The system rewards player engagement, not character-sheet optimization.
3. Announce the odds before the roll, never after. The stated probability is a contract. A player can withdraw after hearing the odds, but cannot negotiate once the die has been cast.

Roll No. 2—Opposed Checks

An opposed check directly compares two conflicting forces. Each side rolls a d20 and adds the indicated value. The higher result wins. The effect that caused the check specifies what happens on a tie.

The most common opposed checks are:

Check	Formula
Reflex check	Reflex Save against Reflex Save
caster level check	1d20 + CL against 1d20 + CL
DC check	1d20 + DC against 1d20 + DC

A character's Reflex modifier is their Reflex Save. Without a class, it equals DEX + level. With classes, it follows the Save quality assigned by the class: a good Reflex Save adds the character's full level, while an ordinary Reflex Save adds only half.

There is no separate value for priority, attack, or defense. Whenever the rules call for a Reflex duel, the character uses their Reflex Save.

The Reflex Duel (Priority)

When two actions conflict in time—who strikes first, whether the spell fires before the arrow—each side makes a Reflex Save. The highest result acts first. On a tie, roll again.

A duel is not limited to two participants. When several actions compete for the same instant, each participant rolls once and the results order every action from highest to lowest. Tied participants reroll without changing the rest of the order.

The Declaration Bonus

Declaring first means exposing your intent: the opponent gains the information needed to react, and you risk being countered. The game rewards that risk.

The character who declares their action first gains +5 to the Reflex duel or +25% to their result, at the GM's discretion.

The percentage applies to the total result after rolling the d20 and rounds down like everything else. The GM calibrates it for the table; some groups prefer a subtler bonus of about 10%.

The exact number matters less than what it prevents. Without this bonus, waiting is always the best strategy: everyone lets someone else commit before reacting with full information, and reactive combat freezes. The declaration bonus makes boldness viable.

When to Roll—and When Not to

Never roll the duel before actions are declared, and roll only when their order actually matters. The Reflex duel is the game's only initiative mechanism: there is no initiative roll at the beginning of combat and no fixed turn order to track. See the Reactive Combat chapter.

Roll No. 3—Saving Throws

When the world acts on a character, they resist with one of three Saves:

Save	Formula	Resists
Reflex	Character's Reflex Save	anything avoided by moving
Will	1d20 + WIS + level	illusions, fear, mental manipulation, invisibility
Fortitude	1d20 + CON + level	poison, disease, exhaustion, transformation

Compare the Save with the effect's DC. For a spell, DC = 10 + CL/2 + the caster's magic attribute. For an environmental danger, the GM sets the DC; see the Environment chapter. The defender wins a tie. Classes can replace the level bonus for any of these three Saves with their own progression.

Advantage and Disadvantage

Some feats, items, or circumstances grant Advantage on a roll: roll twice and keep the better result. Disadvantage is its mirror: roll twice and keep the worse result. For example, Osseur's Mental Stability gives him Advantage on Will Saves against illusions, invisibility, and mental manipulation.

Rounding Convention

When a calculation produces a fraction, retain it through every step. Round the final result down once.

Round each independent value separately. Round a DC, derived attribute, or number of slots when calculating it. For damage, retain fractions while applying bonuses, percentages, critical hits, and DR, then round down the final damage of each attack.

With CL 5 and INT +8: 10 + 5/2 + 8 = 20.5, resulting in DC 20.

Attacks: No Roll to Hit

An attack that is neither dodged nor parried hits automatically. Roll damage directly. Defense is not a passive statistic: it consists of an active choice by the defender—dodge, parry, or shield; see the Martial Combat and Defenses chapter—and passive reduction from armor DR.

Accuracy is not a separate roll. Anything that would increase the chance to hit in another system instead grants a bonus to the attacker's Reflex roll during a dodge or parry duel. A more accurate strike does not ignore armor; it is harder to dodge or parry. Any old “attack bonus” from an item or feat becomes a bonus to the attacker's Reflex roll.

The accompanying d20. Roll a d20 with the damage of every attack. On a natural 20, the attack is a critical hit: multiply its damage by the weapon's multiplier—×2 by default, ×3 for an axe, and so on. This d20 serves no other purpose.

Chapter Summary

• General uncertainty → prescribed chance roll (“X out of Y”; low is success).
• Direct conflict → opposed Reflex or caster level check. Reroll ties in a Reflex duel.
• Declaring first → +5 or +25% in the Reflex duel. Waiting must never be the best option.
• The world acts on you → Save against DC.
• Attack → direct damage, mitigated by dodge, parry, and DR.

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