Isagi is a fairly tall teenager with an average build. He has short navy blue hair that leaves V-shaped bangs between large blue eyes. While attending Ichinan High School, he wore an unbuttoned blazer over a white tank top and striped tie. In Blue Prison, Isagi wears a regular suit (black with gray stripes) and a tracksuit. During the first tryout, he wore Team Z's blue jersey and Team Z's gray boots. During the second tryout, he wore the white team's.