User blog comment:IamJakuhoRaikoben/Chapter 398: The Final Duels, Review./@comment-4449950-20140902085348/@comment-7418318-20140903091927

That's actually a nice idea. If he using the Ice Devil Slayer magic would greatly exhaust him to the point of it being only useable for a short time and leaving him almost or completely incapable of fighting when it wears off, I think I'd even be fine with him haveing it permanently.