Rosalina

Rosalina, known as Rosetta (ロゼッタ, Rozetta) in Japan, is the adoptive mother of the Luma race and overseer of the Comet Observatory; she was voiced by Mercedes Rose. She first appeared in Super Mario Galaxy for the Wii and later on a minor role in the sequel Super Mario Galaxy 2. She has also appeared in both Mario Kart Wii and Mario Kart 7 as an unlockable character and is confirmed to be a playable racer in Mario Kart 8 . She was rumored to be an Assist Trophy in Super Smash Bros. Brawl, but it was never proven. She will be a playable character in Super Smash Bros. for Nintendo 3DS/Wii U.

Character description
Rosalina wears a silver crown, has platinum blonde hair with a side-fringe, a frilly light blue dress, and carries a wand. When she is driving (Mario Kart Wii only), a small, yellow Luma floats around near her head.

In Super Mario Galaxy, Rosalina made her first appearance when she taught Mario and Luigi the Star Spin. The player also may optionally view Rosalina's shrouded past in the Comet Observatory's Library through unlocking chapters of Rosalina's storybook, while progressing through the game. The mysterious storybook read by Rosalina herself details how she came to meet the Lumas and build the observatory, as well as her childhood struggle to overcome her mother, father, and brother's deaths.

Rosalina appears in a non-playable role in Super Mario Galaxy 2. A "cosmic" version of herself also appears as part of the game's 'Cosmic Guide.' At the end of the game, after Mario saves Princess Peach, Rosalina comes in front of Starship Mario and thanks Mario for saving her lost one and the universe.

In Super Smash Flash 2
In Super Smash Flash 2, Rosalina appears as a background character. Around her, there is a black Luma called Polari. She doesn't make any interference during battles, so she's merely a background character. She appears on the stage Galaxy Tours; in the area Comet Observatory in front of the beacon.

Trivia

 * Rosalina is the first background and non-playable character who has appeared in the Super Smash Flash (series) before her confirmation in the Super Smash Bros. series.