Barbara comes from the Wii U exclusive Rayman Legends. Like Rayman, Barbara is an Ubisoft creation, and since Ubisoft has made several Wii U titles, and Rayman's porbably in, why not choose her? She's a viking, and has a fighting style not seen in Brawl.
B. Berserk Swipe: Barbara swings her axe rapidly.
<-B-> Running Hack: Barbara runs and swings her axe horizontally at the opponent.
B ^ Helmet Wings
B V Low Axe Swing
Final Smash: Bombs
Barbara runs around the arena as bombs fire from cannons and land onto the stage.