From Bulbanews, your community Pokémon newspaper.
Has same moves as in Super Smash Bros.
Greninja in Super Smash Bros. for Nintendo 3DS/Wii U
A Greninja based on the playable character in Super Smash Bros. for Nintendo 3DS/Wii U will be available for Japanese players. Greninja will come with the moves Water Shuriken, Shadow Sneak, Hydro Pump and Substitute. It is level 36, has no held item, and has the Ability Protean. It has the original Trainer 「スマブラ」 SmaBra (Smash Bros.) and the ID number 09134. It at least can be male and can have a Timid Nature, but it is not clear if these are fixed or random.
To obtain it, Japanese Club Nintendo members must register both Super Smash Bros. for Nintendo 3DS and one of Pokémon Omega Ruby or Alpha Sapphire before Jan. 20, 2015. Players who do this will be sent a serial code between Dec. 9, 2014 and Jan. 29, 2015 that will give the player Greninja. This code must be redeemed by March 25, 2015.