Well, I suppose the cop-out answer would be ‘the Pokémon’… but I’m not even sure *that’s* true; I’ve more than once contemplated the idea of a Pokémon fan-fic without any Pokémon in it.
I’ll just let you all muse on that one for a minute.
Seriously, though, I’m really not sure you can pin that down to anything. For me, the core themes of the games are the joy of discovery and the importance of living in harmony with nature. You could write a Pokémon story that isn’t about those things at all, though (I mean, people have), and I suspect that as long as it had the creatures in it, people would still accept it as ‘Pokémon.’ For a moment there I thought about saying ‘well, partnership between the creatures and humans has to be important,’ but then again, Mystery Dungeon. You can say ‘friendship has to be a central theme,’ and I think that’s probably true, but it’s also far from unique. It’s sort of a whole mess of things, and you can go without any one or two of them.
Pokémaniacal 