Hey guys, one of the possible characters that one of my players will be creating is going to be a guy who will be invisible to sight, sound, smell, psychic abilities, etc... I'm a bit worried that a character like this could destroy plots. I could see a constant, "I go behind him and snap his neck" or something to that extent (maybe not a kill, but a defeat for the villain). If possible, I'd rather not disallow what a player wants to play but I also don't want to cheese the game and have to have major villain have the ability to sense him.
We haven't talked about disadvantages yet, so that's still up in there air, but there's no guarantee that he will take power related disadvantages.
Anyway, what are your suggestions on what I should do?