Pokémon X and Pokémon Y

The only pokemon to ever gain a second type was Magnemite and Magneton, but yeah, dual types did exist in 1st Gen and Bulbasaur is the only starter that starts as a Dual Type.

And by the way, here are bigger and cleaner pictures of the Legendaries artwork:
Xerneas
Yveltal

I really love Xerneas's design, especially the eyes and the shape of the head, it's interesting to get a closer look and see that the coloured parts on it's antlers aren't gems or lights like I originally thought, they look more like brightly coloured roots. It's definitely my favourite of the two. Can't wait to see what they look like ingame.

For that matter, I can't wait to see a lot of pokemon in the game. Can you imagine pokemon like Groudon, Aggron, Volcarona, Arceus ect in glorious cel-shaded 3D? So excited.