|“||You're getting better, four eyes. Are you training in secret?||”|
Inukai is a tall young man with dark blonde hair and olive green eyes. His battle uniform is a black full suit, although he doesn't wear a vest (unlike Ninomiya and Tsuji). His unit's emblem is located on his necktie.
Inukai is very playful, stepping in the crunchy snow and enjoying it despite the fact that it left him open, at the start of the four-way Round 4 match. He is shown to be very friendly to others, and never stops smiling, not even in battle. However, although he retains his humorous side in combat, he is nonetheless focused on his objective.
He is very playful with Kuroe, playing with her twintails when they were idling about.
He is aware of Kageura's contempt for him, but is not bothered by it.
- "Sumiharu" (澄晴?) means "floating and cloudy", while "Inukai" (犬飼?) means "dog shepherd".
- His gun Trigger is based on a FN P90 personal defense weapon.
- He likes planes, hot dogs, and grapes.
- With the communication skills beaten into him by his two older sisters, he can be friendly to absolutely anyone.
- He was ranked 24th in the second popularity poll. Additionally, his voice actor Kenta Tanaka was one of the "characters" ranked 130.