Eden Dungeon is a three-level dungeon full of customized dragons. On the first level, you can find Petite and Deleter. On the second and third levels, there are Ferus, Acidus, and Hydro. The third level also has Nidhoggr's Revenge, a dragon MvP that must be summoned by killing 100-200 mobs in the third level. Note that all these monsters are customized and are much stronger than regular mobs.