Behemoth

is the leader of the powerful army that works directly under the Demon Lord and Lord En. He has been mentioned several times, but finally did his first appearance after the Oga/Beel Body Switch incident, looking for Oga in the Saint Ishiyama building. He has the appearance of a simple old man, though this could be only a disguise, as his powers were clearly threatening. He easily defeated Hiromichi Gō and Ichirō Shinjō and then proceed to search for Oga. He was later ambushed by Ittōsai Kunieda, Genma Isurugi and Zenjūrō Saotome, though he didn't fight them back, saying that he only came to greet his new neighbors. He then revealed to have build the Akumano Academy in the grounds that used to be Ishiyama High.

Personality
Being introducted in his old man form he is shown to be calm to the point of not reacting to four opponents attacking him only to transfer to right in front of oga to issue a war declaration