Kinzoku Slime wo Taoshimakutta Ore ga [Kurokou no Ou] to Yobareru made: Ie no Niwa de Kyokushou Dungeon wo Mitsukemashita

A large hole appears in the garden, from which a metallic slime emerges each day. Yuuma Mitaka, an unremarkable high school student, spends his time eliminating these slimes. Over time, his body begins to change in response to this routine. His evolving ability, however, has a drawback: it resembles a monster when active, making it something he must keep hidden. As his unusual nature becomes more pronounced, it becomes clear that his existence could have far-reaching consequences.