Gen is one of the main protagonists of Kaiju No. Gen is a tall, athletic young man with a lean yet muscular build. This allows him to switch his hairstyle between a black bob with hints of grey generally when he is off-duty and slicked back, revealing the majority of his grey hair mostly during combat.
He also has sharp, red eyes magenta in the anime and when using RT and his eyebrows are very short and thick. As a teenage officer in the First Division, Gen was shorter and lankier than he is now, but sported the same signature hairstyle he currently wears. As a Defense Force captain, Gen wears the normal Defense Force combat suit with a respirator mask and his personal weapon.
He also wears a black trenchcoat before his missions. The suit also includes a black and grey jacket. Despite showing an apparent serious demeanor, Gen hides a lazy and childish personality, overreacting when slightly annoyed by something. His unprofessional demeanor brings him to give priorities to futile things over work like his videogames and action figures, [6] or his followers on social media.
Nevertheless, once he arrives on the battlefield, Gen's attitude changes radically, becoming very serious and dedicated to his work as captain of his own division, giving specific orders to his subordinates. When confronting other people, Gen seems to be very informal and rude as he casually speaks up to director general Isao Shinomiya [5] and gets mad at Eiji Hasegawa whenever the latter scolds him.
Like most members of the First Division, Gen has a strong rivalry towards the Third Division , specifically with vice-captain Soshiro Hoshina , who often teases him in front of his subordinates, leading to verbal arguments. Although he holds the title as "the strongest", Gen was never once able to beat his former mentor, Isao Shinomiya.
