Bosses are high-level, stronger-than-natural enemies which are not naturally found in the world. They are usually located at the end of a Dungeon. Each Boss will have its own Reward Chest at the end, which can only be accessed when the boss is defeated.
Many Bosses have unique abilities native to themselves. For example, Azoth, the boss featured in the image to the right, has a chance to spawn additional zombies near the player as the fight progresses, and The Demon's Lotus will close and open its mouth, revealing more enemies of varying strength and speed as the fight goes on.