There are two ways to do this:
#1: But Inhuman Speed, Strength, etc. Possibly add in Feeding Dependency (Magical Energy). Say that these powers are from using magic internally. You are now done.
I'd probably use Human Form instead of Feeding Dependency, if I was sticking to canon Powers.
Some people use Modular Abilities for stuff like this.
A form of Sponsored Magic might be appropriate as well.
Custom Powers to look at:
Supernatural Martial Arts, Magical Self-Enhancement, Limitation, Variable Abilities, Alternate Magical Paradigm, Natural Weaponry, Superhuman Acrobatics, Eight Gates Released Formation, Might Over Magic.
(They're all on
the list. Which is searchable, fortunately.)