I'm not sure how to express this 一刀両断 properly. In this context, I think the author makes a pun of a cool-sounding skill name (which i don't know how to make it sounds cool in English, it sounds cool in my mother tongue though) and Youki's Iris.
Right up とか Left upIt looks like a coffee bean.Since he's half human half phantom, I'm not sure how to do with his Kimono's neckline.I make a slash on the Iris.
Youki has only one slash instead of two like Youmu.
Split in two with one slash.YoukiYoumu