Both the Japanese and English official website announced the new addition to the fifth generation family. Both Pokemon will be featured on the box cover of the games.. Reshiram (レシラム) for Black and Zekrom (ゼクロム) for White. According to the Japanese site, the two Pokémon have a strong connection to the history of Isshu and are key to the games' story. English names not yet announced.
In my opinion, Pokemon is starting to remodel their images and cute and cuddly ones (even legendaries) are starting to turn into what I could contrast with Digimon and other monster games; fierce, brutal-looking and more mechanically designed. But oh well, Pokemon is Pokemon. This evolution does not affect me at all. It would still be the best cartoon/anime that Japan had created (in my own opinion, of course).