I research how to insert new pokemon (not replace existing pokemon) to rom BW2, and successfuly added new pokemon on it...
Well, before that let me explain the case. My new pokemon just call it as POKEMON X. I set up this Pokemon X to encounter in all tall grass in route 19, then I testing it by running into tall grass in route 19.
as my expectation this POKEMON X appear, BUT in wrong form (sprites), he use magnemit sprites as his appeareance and his name shown "?????? wild pokemon" ! I know this my POKEMON X from his "move and ability" that I set up before.
I think rom just recognize all pokemon on his "national pokedexter data" or something like that. Now my question, how we can registering/adding new pokemon data and his sprites? or where all pokemon data stored? is it possibly to repointing sprites and add new pokemon sprites to overworld sprites?