Genya was a foul-mouthed and ill-tempered boy who declined any support from others and showed a little interest in being polite or showing any kind of courtesy. He roughly handled Kanata Ubuyashiki during Final Selection by grabbing her hair and screaming at her harder, which results into Tanjiro Kamado breaking his arm. His ill-tempered traits and brash way of speaking is much like his older brother Sanemi Shinazugawa.

However, He's more socialable in present times. 