Mystic has been training with Waribashi for some time (See "Demons,Mages,and Magic" for more info) I'm thinking about making her a bit stronger than natural so I need help!!! Here are the choices:

have her look the same, but DBZ-ify her a bit (Energy comes out of hands)

make her be able to make her whole body an element (firegirl, watergirl,etc)

Make her be able to have a psychic ability concerning the human body (As a lot of elements are in the human body).

Well, considering that she already contols the four main elements along with any bladed weapon of her choice, I'd actually say she's powerful enough as it is, she'd just need to hone her abilites and learn to use them in new, more powerful ways (using her wind powers to mimic gravity, compressing her fire or water with wind, so that it's like a small bomb, combining her control of fire and earth to control lava, etc.), but if you'd absolutely insist on it, I'd go with the making her body into an element (one element I'd say). But I still think it'd be better for her to learn to master her current powers better than to give her a new one.

I agree with Marx, just give her more refined control over them, let her discover new ways to use 'em.

Or go with one elemental transformation.