Twilight Wave (Hagure, 破暮) is Kuguri’s innate art: bank kinetic energy and heat, spend later. He is Hishaku. Chihiro copies Iai by watching him and the house style at the Kyoto Bloodshed Hotel. The guy with the scar is a weekly title in that corridor.
File: Kuguri, Iai, chapter 70. Official chapters: VIZ / MANGA Plus.