Isekai Maou to Shoukan Shoujo no Dorei Majutsu Ω

Synopsis

The group is intercepted by Fanis' fleet, as she believes Diablo is working with Varakness. They explain their plan to retrieve an item from the dungeon that can cure everyone of Death Knell, but she doesn't believe them and orders them arrested. They escape when Diablo triggers an earthquake. Gewalt arrives and offers Fanis his services, learning of the dungeon. Four days later, the group arrives at the dungeon deep in the desert, but Lumachina does not have long before the Death Knell will kill her. Diablo conceals the fact that he built the dungeon. After defeating the guardian at the entrance, they encounter a labyrinth. Horn had prepared a map, but it is useless because the walls shift over time, so Diablo simply blasts through the walls. After battling monsters, they are suspended in a basket over a river of lava and must answer trivia questions to pass, which they achieve. To pass another level, they must entertain an army of ape-like White Jaegers with a song and dance routine. On another level, they must move along a narrow ledge above a raging river. Gewalt ambushes them and nearly kills Lumachina, but Horn tackles him and they both fall in the river. Diablo tells the others to keep moving and jumps into the river to save Horn.

(Source: Wikipedia)