The ability seems really cliche. Some others here are but they're simple enough that it's not a big deal but this one is so specific that it just seems really over the top.

Ability aside, the whole point of the school seems to be to train students in using their AEDs. The club is pretty redundant and this makes most of the biography irrelevant. No other character is in any club remotely combat related and instead use their club to expand on their character. It just feels like you're trying too hard to make your character be this quiet, strong, mysterious loner that I doubt any of the others characters would want to interact with. To be honest, the character is just boring.