Beelzebub (ベルゼブブ, Beruzebubu) is the 2nd demon of the Reverse Kabbalah.
Beelzebub's true form is that of a huge fly which can cause a tremendous wave to form (said wave can consume an island) with one flap of its wings.
Beelzebub used the alias Ikaros, the ruler and creator of Rock Bird City. This demon has demonstrated the power to release worms from any part of his body, whether to regenerate lost parts (except the head) or to destroy targets via digestion. He can also generate bubbles that control the movement of whomever is encased. Rock Bird City was in fact built around Beelzebub's gigantic body, which is called to join the smaller avatar seen thus far for its final released state. This form can create massive orbs of energy. After the majority of his body is destroyed by Jio, with the help of friends, he was captured by the Zenom Organization and inserted into the reverse Kaballah. When his last moments after transformation he would beg Jio to save him calling them "Friends." And that they are the same.