The grandfather of Aoi and Kota Kunieda who masters the shingetsu style.
He is the master Shingetsu style of martial arts, who has been teaching Aoiand will begin teaching Oga . It also seems to be aware of the powers of evil, saying Oga would soon be the time that teach you how to use them.
Ittousai Kunieda, who is created by Ryuhei Tamura, has no information regarding any inspiration used to create him. He first appears in Beelzebub volume 5 and episode 22. His Japanese voice actor is Hiroshi Iwasaki.
Even though Ittousai is elderly man, he still has fast reflexes and strength. For example, he can dodge Oga's attacks quite easily.