Manga Related Question here. What is the title of this manga?

The details I recall about this particular manga is that the hero defeated an evil, probably a demon king, and then vanished. The hero is kind of goofy, kind of like a country boy but is uber strong. The settings now is that of a school to train future heroes. The heroine is a girl that is like the president of the school council with fans and all. The hero then went to the school(nobody recognizes him except for the king which he is buddy-buddy) and the hero and heroine met. The school held a tournament as per the king's request and the winner will have some sort of sparring with the legendary hero. The heroine challenged the hero to join and not lose until they meet in the finals(again, nobody knows he is the legendary hero except for the king). The heroine has a cursed sword passed down from her family. The curse actually took over her in the tournament and the hero had to save her. I think the her lost some or most of his power thru some unknown means and is trying to get it back. That is all I can remember.