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In the early chapters, he attempts to 'pass on' Beel to other students at Ishiyama, thinking that if he can find someone stronger and more evil than himself, the baby will attach himself to that person instead. The manga follows Oga's life as he tries to raise the child while enrolled at Ishiyama High. This baby turned out to be the son of the great demon king, and Oga has been chosen as the one to raise him, along with the baby's maid, Hilda. Oga pulled him to shore but the man split in half, revealing a baby boy inside.
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One day while doing 'laundry' by the river, he saw a man floating downstream. The story starts with Oga telling his best friend, Takayuki Furuichi, the strange story of how he found a baby. The story follows Tatsumi Oga, who is a first year student at a school for juvenile delinquents called Ishiyama High.
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