Kaibutsu Chuudoku

In a city known as the "Masked City," people consume a "monster supplement" to transform into primal beasts, shedding rationality and embracing freedom through anonymity. This is a government-sanctioned "slum" where individuals escape the pressure of a highly monitored society. In this setting, a vampire named Zero and his werewolf companion Tsuki work as street cleaners, tasked with eliminating various creatures. They pursue hit-and-run centaurs and confront urban legends, including a deadly encounter with the "Medicine Witch," which alters the course of Zero and his friends' lives.