You can do both, or either. That part is up to the players, and I'm cool with it either way. I can figure out a way to get a canon pup there, and I'm actually good at weaving priginals into a world of the player and I can get together and work on history and stuff together. :) When I DM, I tend to be all about the players (although I RP too), so I'll be able to fit whatever it is you come up with just fine. :)

So, if you want to do an OC, go for it. If you want to bring Cloud in, I'm down with that as well.