Residents of District 37

A sanatorium famous for its psychiatric patients hides at an inhabited area 6000 meters below sea level. Rumors has it that those so-called madmen are entities beyond mortals. The life of mortals are equated to fireworks while theirs are closer to an atomic bomb. At Eastern Zhou, 307 B.C. — 2300 years ago. (Source: Bilibili Comics) Note: Chapter count includes a prologue and 8 extras.