Ybur's heart was somewhat heavy.
King Kane was decisive—he must have been prepared to sacrifice himself long ago. The moment he realized resistance was futile, he decisively gave up fighting against the Evil Dragon Curse, and the vengeful flames instantly burned him to ashes. After all, the Abyss is taboo in everyone's eyes, a constant threat looming over every creature's head. No matter how much the Abyss had influenced Kane, in the eyes of others, any contact with the Abyss meant he could no longer be trusted.