The Hero Life of a (self-proclaimed) "mediocre" Demon! 5

The twin heavenly dragons, Mithra and Alia, have been enjoying themselves immensely in the brief time they’ve been in Chrono’s class. However, their fun times as students in the Demon King’s Castle is nearing an end as they must fulfill a contract that requires them to conquer a supremely difficult dungeon. Despite wielding extraordinary power as heavenly dragons, the twins seemingly have no chance of conquering the dungeon until Chrono and his classmates offer a helping hand. Will a group effort be enough to overcome a dungeon that crushed two heavenly dragons?