The Otherworlder, Exploring the Dungeon, Vol. 2 (light novel)

Continuing to work their way through the Tower of Legions on their quest to reach its 56th floor, Souya and his party decide to take on a dangerous new monster-the dragon-turtle Midranga. Little do they know, however, that this decision portends a series of devastating tragedies... As their hunt leads them to the 13th floor, shocking truths and surprising developments come to light. Is this where the adventures of Souya, Lana, a, Bel, Shuna, Zenobia, and Arvin meet their end?!