*Bows* Sorry. Really I am. It happens, and I don't mean to. 

So, you like the Positive and Negative idea? It keeps things simple, and it a concept that's easy to work with, I think. 

Poor doggie, and poor you! I hope it didn't puke on anything important.

For our characters I think it would be interesting for them to be made of both, but each of us made more of one than the other, that way we're not identical. Does that make sense? That way we already have the base inside of us of HOW to mix the energies, but we're still relatively different. Oh, and a thought, to avoid "These are my creations, those are yours" happening between our characters, how about everything HAS to be made of both yours and my energy for them to truly work?