Original Posts:
1 2elemental magic based on exchange, trading control over the element, with parts of the body.
If a person dabbles into elemental fire, they'll start becoming more and more fire-like (glowing veins, emitting smoke, and even being on fire) as they gain more and more control, same for the other elements.
They can even trade limbs for elemental control, like giving up your arm, and getting an elemental stone arm instead, which gives control over earth through that arm.
The naming is based on "Element" and "Kropp", the latter meaning "Body".
The E'lement K'ruppt is irreversible, and is rather insidious, slowly trying to spread to more of your body. The end result being that you inevitably turn into an elemental.
The shape is based on the soul, so you don't even need to have the limb to offer it, it will just generate the elemental limb.
This takes time however, so a severed head can't just gain an elemental body in the time it takes to suffocate, it takes minutes to hours or even days, depending on how much of your body you trade.
The E'lement K'ruppt must be regularly reinvigorated at a source of it's elemental power. If it's not, the body parts will lose power, beginning to dissolve, crumble, burn weaker, etc.
Invigoration is hastened by meditating while it's going on. Water requires presence to running non-stagnant water. Fire requires a living flame, any flame will do (sunlight is the best though).
Earth requires a place with healthy earth (natural and supporting life (flora and/or fauna), caverns is the best). And Air requires basking in free flowing air from the winds (mountaintops are the best).