Iffdahsil

60 feet. DC 45 fortitude

A creature entering or starting its turn in the aura that fails at a Fortitude save becomes Doomed 1 and Drained 1. If the target was already doomed or drained, the values of these conditions increase by 1, to a maximum of doomed 3 and drained 3. A creature that dies while doomed 3 and drained 3 in this way disintegrates into black sand.

Unlike most undead, Iffdahsil isn't destroyed at 0 HP. Iffdahsil's fast healing continues to function normally, though on any round it begins its turn at 0 HP, it is Enfeebled 4 and Slowed 1 until the start of its next turn. While Iffdahsil is at 0 HP, it can be killed permanently only by simultaneously exposing it to direct sunlight (or a 10th-rank Sunburst spell) and casting a Miracle or Wish spell (or similar magic) directed at destroying it.

(3d10+17)[piercing], DC 41 fortitude

Note: A DC was not provided for this ability by Paizo. The DC present here is a moderate DC for the creature level according to the Gamemastery Guide creature building Tables.

A creature that begins its turn inside Iffdahsil takes 10d6 void damage. Iffdahsil gains temporary HP for 1 minute equal to half the damage dealt.

DC 43 reflex, 10d6 void, , Rupture 45

Iffdahsil deals 8d8 piercing damage to each creature in a 10-foot area (DC 43 reflex save) and can also attempt to Grab any creatures who critically fail their save as a free action. Iffdahsil is then Off-Guard until the start of its next turn.