I'm prepping for a new game for some players and am trying to figure out the best way to make this work. Long story short, all the PCs will be mortal incarnations of some elemental/natural/primal force (air, trees, rage, etc). Unfortunately, due to Far Realm intervention, they don't know they are (the players, of course, do) until something triggers the release of the spirit/force.
Think Avatar-state in Avatar: TLA, if you've seen it. The game will be run in 3.5, and I'm looking for ideas for how to handle the mechanics of the alter-ego taking over when it does.
Eventually, I want the players to be able to coincide and/or conquer the spirit and have control over the power granted, but I'm not sure what those powers are/how they would work, from a mechanical standpoint.
Any ideas or suggestions are welcome. Thanks.