Originally Posted by
CidtheKid
On the other hand, making it permament could have some interesting ideas to it. If its permanent, then it probly remains in the body, which you could then extract upon the users most likely incredibly violent death. Or extract through other means or whatnot. It could become much more expensive, and then you have the whole "only rich people can afford it" coupled with "you can get it by killing people" combo that guarantees plenty of conflict.
Keep the power levels at nothing too big, make getting more power addicting, and you have something pretty cool going on.