pf2e.fyi
From Pathfinder War of Immortals, which isn't enabled.

Divert Destiny

FEAT 6
Activity free action

Trigger An attack or effect would reduce you to 0 Hit Points or kill you outright.

You defy the fate before you, calling on wells of mythic vitality to sustain your life and allow you to persevere. You expend 1 Mythic Point and survive the triggering attack or effect, lose the wounded or dying conditions entirely, don't increase your doomed condition, and are conscious and standing with a number of Hit Points equal to 10 + your level, regardless of how many Hit Points you had before.

Pathfinder War of ImmortalsORC