OP Black Emperor Retires After Defeating Black Dragon... But Monsters Keep Forcing Him to Fight

He was the Black Emperor — the man who single-handedly slaughtered the black dragon everyone said was unbeatable. Then he walked away from it all, tore up his Grade O rank, and vanished without a trace. Three years later, he's "Blank," a scrawny Grade 10 errand-runner nobody takes seriously. He just wants a quiet life: gathering herbs, growing tomatoes, soaking in hot springs. But when monsters no one can explain start swarming a town near the demon forest, and a golem three ranks above anything that should exist shows up at the gate, his old power starts leaking through the cracks — and he can't hide what he really is for long. #isekai #mangarecap #manga #isekaianime