Lucario

Lucario is a playable character in Super Smash Bros. Brawl, entering from the Pokémon series 4th Generation of games. He was confirmed through a Sticker screenshot which showed Lucario's icon at the bottom, but it wasn't officially confirmed until later, when Nintendo started leaking game videos on the game just days before Brawl's Japanese release. It is unknown what Lucario's moveset is, neither is it known what his statistics are, but it is known he'll play a part in the Subspace Emissary, in which he will assist Snake at some point in the game. He also appears to fight Meta Knight and the Ice Climbers at one point in the story.

Lucario appears to replace Mewtwo, another Super Smash Bros. Pokemon fighter.

Recently, two gameplay videos have been found. They can be found here and here.