Sinking Inscription

On the proc, bonus = (target's missing HP / target's max HP) x 120, added as percentage points of Damage Dealt Bonus. The scaling is perfectly linear in the missing fraction, and there is no extra hundredth here: the result is already percentage points.

Where it lands: The bonus lands in the additive damage dealt bracket of that one hit, and that bracket is then multiplied by the critical multiplier. It is applied before defense.

When it runs: Before the hit is calculated, in the phase where effects adjust the attacker's stats.

What it applies to: Basic attacks only. There is no melee check, no damage type check and no touch tag: any skill flagged as a basic attack qualifies.

Worked numbers

150 physical attack power, a 100 percent coefficient basic attack, target at 0 resistance, critical damage bonus at the default 50 percent.

Rule of thumb: Every 10 percent of the target's missing HP is +12 percentage points of damage on the proc.

Things the tooltip does not tell you

• The counter runs 1, 2, 3, 4 and then subtracts 3 to land back on 1, so the first proc comes on the 4th qualifying basic attack and every 3rd one after that.
• The counter is hidden. The effect is not exposed to the player, so there is no way to see how charged it is.
• The max stack of 4 on the table row is that counter, not a 4-attack cycle.
• Multi-target basic attacks give each enemy its own hit, so the counter advances once per enemy struck. Derived from the data shape, not bench tested.
• The bonus is scoped to one hit and is additive with the other damage dealt bonuses, so it does not multiply them.

How it interacts with other effects

• Shockwave compounds. The splash is a share of the damage that landed, so a Sinking proc multiplies it by the same factor: at a 72 point proc the splash goes from 67.5 to 116.1.
• Storm gains nothing. Its proc scales off physical attack power on a fresh execution, which never sees Sinking's bonus.
• Storm and Shockwave procs do not charge the counter either. Their publisher is an inscription rather than a skill, so they fail the basic-attack gate.
• Healing Touch kills it outright. With a nature staff equipped and Healing Touch learned, the basic attack becomes Healing Touch, which publishes a heal and not damage. Sinking only listens to damage, so on that unit it never charges and never procs.

Read out of the game binary of build 24354931. AFFECTER_SinkInscription.Passive_SinkInscription.SinkInscription@0x924FE8, AFFECTER_SinkInscription.Passive_SinkInscription.<SinkRoutine>d__5.MoveNext@0x9255EC, AFFECTER_SinkInscription.Passive_SinkInscription.<ExcessiveBleedingRefreshRoutine>d__6.MoveNext@0x9254C8, SKILL_HealingTouchAttack.<SkillRoutine>d__0.MoveNext@0x8D048C