A Japanese Olympic sparring athlete. He has 3 identical twin brothers. The oldest one is Sekido, a physics teacher with anger issues. The 2nd is Karaku,a carefree aeronautical engineer that does things however he wants. The last one is Urogi, the most childish grown man on earth who's a zookeeper. Aizetsu is the 3rd born between this quadruplet

He also has a younger brother in 1st year middle school. Named Zohakuten who's so mature yet so rude for his age. Their father is Urami,a 199 cm 60 y/o man who resents everything