It's part of the final battle of the Grave Danger Quest.
Damage Taken From Elements
Rewar the Bloody never retreats.
The challenge during the fight against Rewar is keeping it vulnerable. If one of the Fetters is alive, the boss will not take any damage, thus the Fetters must be killed as quickly as possible. The best way to do this is to position the players in a way that the boss never moves when it change forms and also that both Fetters get hit simultaneously when a Great Fireball Rune is thrown at the center of the room. This way, damage to one of them will always be dealt when the runes are thrown and no attack turns will be wasted.
- This creature drops no loot.