I just bought Pokemon Alpha Sapphire for myself and Omega Ruby for my friend. I also played the X/Y games and I have Pokebank. The problem is: I didn't play games of the 5th and 4th generation. I basically skipped the Nintendo DS games and started playing again with the release of Pokemon X/Y.
My question is: Is it possible to complete the Pokedex with only the four 6th Gen games (X, Y, Omega Ruby, Alpha Sapphire)? Or will there be some unobtainable Pokemon?
I'm not talking about the rare legendary ones like Celebi, Arceus etc. I just want to know whether I need to use a 5th gen game or not to "Catch 'Em All".
Best Answer
Researching the answer to this question, I encountered two extremely helpful lists on Serebii.net:
Diligently comparing the two lists, the only Pokémon that appear on both are mythic legendairies such as Mew, Celebi, etc. Even all the generation-2/4/5 legendaries like Suicune, Cresselia, and Landorus (to name one from each) are available in the Gen3 remakes (many are, of course, gated to one version or the other).
So, assuming the lists are accurate (and they appear to be); Yes, the pokédex is complete-able owning only Gen6 games. Keeping in mind that as soon as the PokéBank was released last February, this was already possible through the GTS - I mean, unless you own all four games, some trading is unavoidable due to how Pokémon games are structured.