1x31 - Beelzebub

The fight between Oga and Miki begins, with Miki seemingly beating Oga with ease. He strikes Oga with a technique which Aoi recognizes to be Hakkyokuken, a martial art form from China. Oga continues to fail to hurt Miki, using a variety of "special moves" which don't seem any different from his usual attacks. Miki begins to power up his most powerful technique, which he advises Oga to dodge due to its power. Before he has a chance to use it, he is interrupted by Nanami, the 2nd strongest of the 6 Holy Knights. She is shortly joined by the final knight, Izuma, the strongest of the six. Aoi senses how much power he has and recognizes that they have no hope of defeating him. The students return to their classroom to find a notice, declaring all of the Ishiyama High students who were present on the rooftop expelled. The students go to the Counselor's office to complain, and are told that they have a chance to avoid expulsion - by beating the 6 Holy Knights at a sporting event at the upcoming school festival. The students reluctantly accept and leave the office.