Episode 21— Who Do You Think Is Ishiyama's Strongest?

Furuichi is abruptly summoned by Alaindelon at 4:00 A.M. to witness a battle between Oga and Tojo against Hilda, Lamia, and Forcas Rachmaninoff at Ishiyama High. Meanwhile, Kanzaki, Himekawa, and Shiroyama fight Aizawa and Karou but are quickly overpowered, though they refuse to surrender. As Natsume intervenes and defeats Karou, Oga faces increasing challenges in his fight with Tojo, complicated by Beelzebub's activation of the Zebul Spell and an unexpected firework mishap. After a long and intense battle that stretches into dawn, Oga ultimately defeats Tojo with a surprise suplex. Tojo later reveals his personal connection to the Zebul Spell through a mentor figure, claiming himself as the new strongest student at Ishiyama High.