The Demon Berserker is a mob added by the Nether Expansion idea pack. It wields a Steel Battleaxe and spawns in the cells of Demon Castles. It has 40 HP. Before its health decreases to 10 HP, it will do only damage; however, once it is taken down to 10 HP, it does a mighty damage - enough to kill anything without Iron Armor or better in 1 hit. This makes it extremely dangerous.