S1·E3 Are There Any Strong, Ruthless Bastards Around?

When Oga loses some food for Beelzebub and he starts to get hungry, Oga instead uses up a vending machine's worth of yoghurt drink, revealed to be the favourite of the second year delinquent, Hajime Kanzaki. Figuring he may be worthy of dumping Beelzebub on, Oga goes to see him under the pretense of becoming his henchman. After beating his current henchman, Oga is asked by Hajime to throw him out of the window, but instead decides he isn't worthy based on Beelzebub's expression and knocks him out instead.