Mirage's valkyrie costume
Danielle Moonstar is a Native American of the Cheyenne Nation. Moonstar's mutant powers emerged at puberty, but she could not control her ability to create visible images of people's greatest fears. Manifesting the images at unexpected moments alienated her from everyone in her community, except for her parents William and Peg Lonestar, and her grandfather, the chief and shaman Black Eagle.
One night, Dani created a symbolic vision of her parents' deaths. Shortly thereafter, Dani's parents disappeared during a trip to the mountains. Moonstar believed them to have been killed and her dreams were haunted, thereafter, by a vision of a demonic bear, whom she believed to be responsible for their deaths. In fact, Moonstar's parents had been transformed into the demonic bear by an as yet unrevealed cause. This bear intended to work the same transformation upon Moonstar, but the spells of Black Eagle kept the demonic bear away from her.
After her parents' disappearance, Moonstar was taken in by their friends, the Roberts. Danielle became close friends with their son, Pat. After she had been at the Roberts' home a week, Moonstar was at Sunday dinner with them, when Pat said something to her that provoked her. Moonstar lashed out at him with her psychic power and the images of the objects of Pat's greatest fear and desire appeared before Pat and his family. Moonstar fled to the mountains, where Black Eagle raised her over the following years.
Finally, Black Eagle sent a letter to Professor Charles Xavier asking him to provide Moonstar with the training she needed to utilize her powers. Xavier had become a friend of his son, William, Danielle's father, when both Xavier and William were in the army. Xavier and William had become blood brothers and Xavier had become acquainted with Black Eagle. When Black Eagle asked Moonstar to go with Prof. Xavier, she angrily refused, believing all Caucasians to be her enemies. In her anger, Moonstar unintentionally created an image of Black Eagle's death as he had foreseen it in a prophetic dream. Black Eagle ordered her to go with Prof. Xavier and she agreed.
Before Prof. Xavier arrived, Black Eagle was murdered by agents of Donald Pierce, a member of the Inner Circle of the Hellfire Club, who intended to overthrow its leader, Sebastian Shaw. Pierce was determined to kill Prof. Xavier, as well as other superhuman mutants. Moonstar, unaware of Pierce's involvement, vowed to take vengeance for her grandfather's death. Moonstar soon found herself hunted by Pierce's agents, but she was saved by the mutant Karma, who arrived along with Prof. Xavier. Dani agreed to work with Prof. Xavier to get her revenge on Pierce.
After Moonstar helped Prof. Xavier and other young mutants he had enlisted in defeating Pierce, she and the other young mutants became members of his new team, the New Mutants. This was a group of young superhuman mutants whom Prof. Xavier trained in the control and use of their powers at the School for Gifted Youngsters. Moonstar decided to remain with them to honor her grandfather's request, despite her initial hatred of all Caucasians, and she soon came to regard her fellow New Mutants as close friends, regardless of their racial background. Dani became an especial friend of Rahne Sinclair (Wolfsbane), in part due to the psychic rapport they shared when Wolfsbane was in non-human form. Moonstar originally took the code name Psyche, but later changed it to Mirage, after the illusions she creates.
Despite her power, Dani was a valuable member of the team in her own right, being the only one to pass the team's first test in the Danger Room. Although the team was originally created because the Professor was possessed by the Brood Queen egg inside of him for future embryos, they stayed together. The team battled the powers of the Brood Queen inside of Professor Xavier that was using Dani's powers to create a horrific landscape.
With Black Eagle dead, the demon bear was no longer prevented from seeking out Moonstar and she fought it outside Prof. Xavier's mansion, where it nearly killed her. Upon discovering Dani heinously mauled, the New Mutants rushed her to the Mid-County Medical Center. The Demon Bear was not through with Danielle and he infiltrated the hospital, thinking to finish the job and possess Danielle's soul. The Bear transported the team to the Badlands, presumably his dimension, where the New Mutants battled the bear. Her teammate Magik used her Soulsword to release Moonstar's parents from the spell they were under, returning them to their human forms. During this skirmish, the Demon Bear had possessed Sharon Friedlander and Officer Tom Corsi and turned them into demonic Native American warriors under his control. They reverted back to normal humans, but Sharon and Tom still kept the appearance of Native Americans. Moonstar was reunited with her parents and she eventually recovered completely from her injuries, thanks to the Doc at the School.
Under Prof. Xavier's guidance, Moonstar not only learned how to keep her powers under control, so that she only used them when she so desired, but also learned how to use her powers to create images other than those of the objects of people's fears. Eventually, Dani and Cannonball became the team's leaders.
Later, Amora the Enchantress kidnapped the New Mutants to Asgard. Dani found herself on Valhalla, where she rescued a winged horse from a group of hunters. The winged horse was one of a herd of such creatures belonging to Odin, ruler of Asgard. The horses were ridden by the female warriors called the Valkyries who guide the spirits of the recently deceased to the Afterlife. Mirage forged an immediate psychic rapport with the horse, whom she named Brightwind after her pony on Earth, and the horse selected her to be his rider. This "bonding" bestowed part of the Odin power upon Mirage, and thus she became endowed with the Valkyries' power to perceive the coming of death. When the New Mutants returned to Earth, Brightwind came with Mirage.
Soon thereafter, Professor Xavier left Earth for an indefinite period of time, leaving his school and the students in the care of his competent associates.
source: http://www.angelfire.com/comics/benriely/
http://marvel.wikia.com/Danielle_Moonstar_%28Earth-616%29
http://www.comicvine.com/moonstar/4005-1463/