1x20 - Beelzebub

Oga reflects on Lamia telling him to take a shower before going to Tojo and sees a silhouette outside his bathroom window and thinks it's Lamia, but it's really Shiroyama, who takes Oga to Kanzaki and Himekawa who tell him they want to team up to beat Tojo and Oga agrees. On the way to Ishiyama High, they are surrounded by a large group of delinquents, which Oga takes care of swiftly. Upon arriving at Ishiyama High, the rest of the school is there to confront Oga, only to have Kunieda and the Red Tails take care of them for him. Tojo sets off fireworks in order to try and cheer up Beelzebub and all the delinquents are captivated by them. Oga confronts Tojo and Tojo is willing to give Beelzebub back only to have Oga tell him that whoever Beelzebub wants to stay with is up to him. Beelzebub's fever breaks and he immediately goes to Oga and climbs on his head, and a flashback shows Oga reconnecting the bond between him and Beelzebub. Just as the episode ends, Oga and Tojo are about to begin their fight.