Every Sacrier has access to Angrrr, even without this passive equipped.
Sacriers start the battle with Angrrr proportional to the amount of HP he/she has. If they take damage the value goes up (the specific amount is based on the amount of HP% lost). If they receive healing, the value goes down.
A Sacrier's Fire spells are designed to increase Angrrr by causing damage to the Sacrier when the spells are cast.
Angrrr is treated as a percentage amount, from 0% when "empty" to 100% when "full". i.e. 1 point of Angrrr is effectively 0.9% of max HP.
- There is no way to 'spend' Angrrr. Only healing decreases your Angrrr level.
- Angrrr is based off %HP, reaching its cap at 10% HP
- While the Angrrr system is unique to Wakfu, Dofus' had an equivalent gameplay design called Punishments (the act of taking damage granted bonuses to the character).