Obliterator

Obliterator is Koi's pet cat and familiar, who was capable of massively exploding. They came from Sylvania Vectress' mystery box in Castle Raven Barrow in the Shadowfell. During the rescue mission at Certis' keep, Obliterator was killed by an undead and teleported by Koi into the corpse well, destroying it in the explosion (and killing Krauss, but he was revived).