Basic premise is:
Normal guy gets attacked by demon and is badly hurt, mysterious girl shows up and defeats demon and uses some power to save guy, but in the process transfers her powers to him. This is very much against her family code and they must find a way to transfer her powers back, but I think the guy has to get strong enough so he doesn’t die in the process. She runs away so her family can’t find her ( they want to kill her ) and eventually they find them both and give them a time limit to transfer the power back.
I know this is a long shot, it’s quite a dark set anime, lots of moody colors and a bit of gore.
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