Rolling the Dice
The crowd chooses what Kessen attempts; the deterministic rules engine decides whether it works.
The d20
Attacks, skill checks and saving throws use a d20 plus Kessen's modifiers. Attacks are measured against the target's Armor Class; checks and saves are measured against a Difficulty Class. Meet or beat the target number to succeed.
Advantage & Disadvantage
When at least 75% of a decisive vote agrees, Kessen becomes Focused and gains advantage on what follows. At 40% coherence or less, the Substrate leaves him Scattered and acting at disadvantage.
Criticals
A natural 20 on an attack always hits and lands a critical; a natural 1 always misses. The result updates the visible game state; Xarnak narrates it but never rerolls or changes it.