He is part of the Dark Trails Quest.
Damage Taken From Elements
It is extremely important to kill the Lesser Death Minions first, before they become stronger. Also, although one would expect items that provide protection from Death Damage such as Koshei's Ancient Amulet to be useful against Shargon, extra attention is recommended as such items will increase the holy damage taken from both the dazzled status and the holy wave. It is strongly recommended to not use Wild Growth or Magic Walls because if you do so, the boss will disappear and summon around 20-30 Death Reapers.