Mavist Island is a U-shaped island in the. Found between Eve Island and Ice Maze Island, it includes a lake, waterfall, and rocky terrain. Scattered around the island are huts, campfires, and 12 treasure chests. Lower levels may find it effective to farm chests here until around level 50.
Astonishingly, a passage to a cavern always opens behind the waterfall, which currently leads to an empty series of turns. It can be reached by walking up to the base of the waterfall and using the prompt to hit B and climb up. The entrance is massive. The area, as well as the island, currently seem to be devoid of any purpose save for chest farming. It may possess a purpose in the future. A specific room in the maze seems to have the makings of a throne room, with a high, rocky pedestal, possibly serving as the arena of a future miniboss.