Mastoma (マストマ) is a supporting character in I Left My A-Rank Party to Help My Former Students Reach the Dungeon Depths!, voiced in Japanese by Shunsuke Takeuchi. The series' music includes "A-Rank Party wo Ridatsu shita Ore wa, Moto Oshiego-tachi to Meikyuu Opening Full『Enter』by L.E.I.", "A-Rank Party wo Ridatsu shita Ore wa Ending 2 Full - 「MIRROR」by Yuki Tanaka".
