Kinzoku Slime wo Taoshi Makutta Ore ga "Kurokou no Ou" to Yobareru Made

Synopsis:

At some point, a huge opening opened up in the yard of a house. There was a puzzling sludge with a metallic body that was shudder and shaking. For reasons unknown, Yuma Mitaka, a dull secondary school understudy, gos through his days eradicating the "metallic ooze" that springs up in the opening each day. Yuma's body changes in an amazing way as he repeats this daily routine! This is a phenomenal Musou dream that starts with a normal day!