The official Pocket Monsters Best Wishes website has reveal the details for the Kairyu (カイリュー) that will be distributed on the Japanese Pokémon Global Link through an unlock code provided to viewers that play the Data Broadcast game during BWS2-N 9 - The Plasma Gang's Ambitions! Pokémon Under Mind Control!! (プラズマ団の野望！操られたポケモンたち！！).

The Pocket Monsters Best Wishes Data Broadcast is an additional segment that allows people with a compatible settop to play a game to capture a Pokémon. During the original TV Tokyo airing, the featured Pokémon could be registered in the data broadcast Zukan by correctly answering a question about it as the ending theme plays. Successfully completing the Data Broadcast for this episode gives people an unlock code for Kairyu.

Kairyu (カイリュー) is level 55 and has the ability Multiscale. It knows the following moves: Dragon Rush, Safeguard, Wing Attack and Thunderpunch.

Source: http://www.tv-tokyo.co.jp/anime/pokemon_bw/news/