Rinsama_'s manga / #orphans(1)

Ughhh poor translation.. Anyway, I love this magic theme thingy!! What made me remember this story was how black haired dude was so mean and cold towards mc. And MC seemed to be the weakest (almost no mana) and no memory of a lot of his past except that they're orphans and childhood friends. BUT it was because black haired dude was in an accident and so MC transferred his mana to him. MC was very powerful and talented before. That's why black haired dude felt bad for MC plus the transfer was done poorly, so black haired dude kept stealing mana and energy from MC if they got close.