Cant remember the name of an anime, please help!!

[E11man]

Hey I've been trying to find an anime i watched a year or two ago. I can't seem to find it and don't remember the name of it, but I do remember a few specific details. It is a magic school anime and I believe it only has one season. The school is all about sword fighting and there is a tournament to determine the strongest student. The main character is overpowered but way underrated. To everyone he seems to be weak but in actuality he is one of the strongest swordsmen out there. Because he seems weak the only way to graduate from the school is to win the tournament. I know this is pretty generic for magic school anime's but a few key character points are that his defense gets better the closer people get to him, I think its referred to as irregular defense, and his love interest is a princess who is crazy powerful for a first year, note: she has bright red hair. 

I know that many anime could be described by this^^ but any help is apprecited.