Kurogasa (S01E06)

Kenshin receives a request from the police chief, asking for his help to take down "Kurogasa," a serial killer who has been repeatedly targeting former Revolutionary warriors. Kenshin and Sanosuke go to escort Jusanro Tani, who received a letter containing a death threat. As warned in the letter, at 1:00 a.m. sharp, Kurogasa appears. His true identity was Jine Udo, a vagabond slayer who had made a name for himself in the assassination business since the Bakumatsu Era. (Crunchyroll)