Critical hits (or crits) are attacks that deal significantly more damage than usual. They have a random chance of occurring, defined by a unit’s luck stat (plus any item effects that increase their crit chance). Any ability/damage that triggers the On hit proc has a chance to be a crit.
Critical hits deal 2.0x damage. If crit chance is greater than 100%, every hit is a crit, and you instead have a chance to double-crit, dealing 2.5x damage. This continues on and on as crit chance gets higher and higher (triple-crit 2.75x, quadruple-crit 2.875x, etc), with the multiplier approaching 3.0x but never reaching it.
I got an omnipotent language model to lay it out below.
Crit chance determines the **tier** of a hit using the following formula:
- **Tier 0** (normal hit): crit chance is 0% — no bonus damage.
- **Tier 1** (crit): guaranteed when crit chance ≥ 100%. The overflow (crit chance − 100%) becomes the chance to roll for Tier 2.
- **Tier N**: each tier's overflow chance rolls for the next tier.
Each tier's damage multiplier is calculated as:
- **Tier 0**: 1.0x
- **Tier 1**: 2.0x
- **Tier 2**: 2.5x
- **Tier N**: previous multiplier + (0.5 / 2^(N−1))
So the sequence is 1.0x → 2.0x → 2.5x → 2.75x → 2.875x → ...
When crit chance is below 100%, each hit has a `crit chance %` probability of being Tier 1, and otherwise is Tier 0.
When crit chance is at or above 100%, every hit is at least Tier 1, and the overflow is used to roll for the next tier — repeating until the roll fails or crit chance runs out.