A couple of years ago, I was browsing the web for something to watch when I stumble across the first episode of this anime that looked kind of interesting.
It starts with the normal main character having a normal day, living a normal life, when BAM! a supernatural creature attacks. I can't remember all the details, but I do remember the female warrior troupe that comes along to try and beat back the creature. Things aren't exactly going well, and the guy is doing his best to help given the circumstances, but things take a turn in their favor when this fairy (and she definitely looked like a fairy) comes along and offers her powers to the boy to save the day. He says yes, defenders win the day, the guy turns out to be the first male to ever gain this power (I think; I mean, the girls seemed pretty hung up on the fact a guy was wielding this power) everyone goes home ready for what's next.
It's not "Luck & Logic" or "Blade Dance of the Elementalers" (Seireitsukai no Blade Dance).