As an undead he has rotten corpse appearance.
After his dead, Zo Gil was turned into an undead and been reborn as a greater demon with Twisted Demon Horn. He is the mastermind of Duchy Capital attack. His purpose was none other than to ressurrect his majesty, Golden Wild Boar King. But maybe he is actually also being manipulated himself, since his head blew off by a delayed magic effect when he is in the middle of speaking about someone, presumably the true mastermind.