All for One and his army. 57 chapters later, they FINALLY defeat All for One. It's not bad right? For Izuku, that's his canon ending. But for the author, apparently that's not the end because they decided to be an asshole and add another chapter.

In the last chapter of the Webnovel, Katsuki and Shoto immediately proposed to Ochako after they defeated the Demon Lord. Ochako rejects Katsuki and chooses Shouto. The author takes it a step further because the next thing they did was even worse.