Your character needs some serious revising. I said I wasn't sure whether there'd be that many witches or not. I should have said: don't make a witch. Even further: Don't make a sorcerer. Sorcerers are even rarer and more powerful than witches, and while I MIGHT allow a witch, I'd never allow a player controlled sorcerer. However, your description of power is nowhere near the level of a true sorcerer's, and is more reminiscent of black blood or weapon blood, or something of the like. You also never explained WHY yours has the power it does, and, You are too old to be a student of the academy in my opinion. Your character is not Acceptable. That doesn't mean it's not salvageable. Please revise it.
Like...Can i make him batman? Ok let me stop messing around. Your are right there are very little but i never thought they all would be super strong. I was having trouble coming up with a non witch soul character who is a villain since you cant find much of them. I could be a monster such as Free, Blair and Mosquito (It is said he doesn't in SE wiki) but even thy contain magic. Its hard to be original with limitation but that will in the end those will help create a interesting character. I am searching in the book of Eibon and found a character but i would like to check with you first before i create it since you never said we can use monsters or not.