*Rosalina /ˌrəʊzɑˈlinɑ/ is a powerful sorceress and the adoptive mother of the Lumas. Rosalina made her debut in the 2007 Nintendo Wii title Super Mario Galaxy, where she serves as one of Mario's allies who helps him when the latter ends up bumping into her after his botched attempt to save Princess Peach at the start of the game, though she has become a recurring character in spin-off games. A powerful and motherly figure, she lives in space with her children, the Lumas, and travels the universe on the Comet Observatory. Rosalina is known for her slight resemblance to Princess Peach but with a mature personality. She also stands at a taller height than Peach and Princess Daisy.

Rosalina is a very tall young woman with fair skin and cyan-colored eyes, with only her left eye visible from a directly frontal view as her particularly large bang of her hair covers her right eye. Similar to Princess Peach, she has defined peach-colored lips and long platinum-blonde hair that reaches to her waist with two hairlocks and two pairs of crescent moon-shaped parting bangs aligned vertically on each side, with the topmost pairs along her forehead, nearly touching her eyes, and the bottommost pairs closest to her neck. For makeup, she uses purple nail polish and brown mascara. While she was young, according to her storybook, her hair was strawberry blonde. She also wore a sleeveless white nightgown.

Her primary outfit consists of a turquoise bell-sleeve gown with pastel blue edges and hem, which is folded toward the shoulders to bare them and, through a triangular opening, reveals white petticoat at its base, along with a silver crown with four gems—two rubies at the front and back and two sapphires at the sides, a topaz brooch with silver star setting, gold four-pointed star earrings, and silver round-toe high heels. She notably appears in this outfit when playing golf, making her one of two female character to participate in a primarily sports-themed game wearing her heels, the other one being White Mage, although Rosalina retains the full-length dress, whereas White Mage sports a mini dress.

Like Peach and Daisy, she has a biker suit when riding bikes or ATVs in Mario Kart Wii and Mario Kart 8. Rosalina's is primarily white and cyan, to differentiate hers from those of Peach and Daisy. Like Daisy, her hair needs to be flowing up to see the heart-shaped decal on the back of the suit. Also, she starts having a ponytail in Mario Kart World.

In Mario Tennis: Ultra Smash, Rosalina wore a sleeveless sports dress that matched the color of her standard gown in cyan. The shoes were teal, and her legs were cloaked in white tights, although the tights were colored silver in Mario Sports Superstars. In Mario Tennis Aces, her footwear is replaced by a set of cyan hard cross trainer shoes.

In Mario & Sonic at the Rio 2016 Olympic Games, Rosalina wears a long-sleeved leotard with a collar for swimming and rhythmic ribbon events. She does not wear her nail polish.

Rosalina is shown to be a wise, mature, motherly and kind woman, who has made protecting the cosmos her mission in life. She is a loving mother figure to the Lumas, caring for her children diligently. She also showed sorrow for her own mother, who apparently died many years before Rosalina met the Lumas. She also uses the phrase "may the stars shine down on you" as a way of saying good luck. A powerful figure, Rosalina has little-to-no fear even in the face of danger, as she threw herself in between Cursa and the Lumas in order to protect them without hesitation.

Rosalina possesses extensive knowledge of the universe and the abilities of the Lumas, as she explains to Mario/Luigi how Lumas are adept at transforming and how they are reborn.

Rosalina is ambidextrous, using her right hand for magic, but her left hand holding her wand.*