BIOGRAPHY
Much of the history of the young woman known only as Wicked remains shrouded in mystery. Apparently, she became quite rebellious in her teenage years, and started dressing in a way that her parents did not approve of. Her mother called her “Wicked” because of this. The family was 
living on Genosha when the Mega-Sentinel attack occurred. Wicked had planned to go out of the house but her mother yelled at her for what she was wearing. The argument did not last long, though, as both parents were killed in the attack on Genosha. Wicked was apparently saved by the manifestation of her mutant powers. [Excalibur (3rd series) #7]
Wicked was among the small number of mutants who survived the genocide, and at some point joined up with another survivor, a boy who called himself Freakshow. How these two young mutants survived on their own on the devastated nation is anyone's guess.
When Charles Xavier arrived on the ruined island nation, Wicked started spying on him, careful so as not to be seen. Not that it mattered, of course, as the world's foremost telepath of course knew he was being watched. Wicked came out of hiding and queried Xavier as to the whereabouts of the X-Men. Wicked was angry at Xavier and confronted him about where he and his X-Men were when Genosha was under attack, as they were supposed to be heroes and protect mutants. 
Wicked told Xavier that she didn't want his pity, not that he offered any, and introduced him to her powers, manifesting several spirits amongst the rubble, where she and Xavier conversed. Wicked warned Xavier that he wouldn't want to be outside after dark, and that he would never get anywhere without the assistance of the spirits. From their brief interaction, Xavier determined that wicked was a courageous young woman with a sense of style and honor.
While Wicked may have had a sense of honor, other mutants on Genosha did not, and several of them had banded together with the mutant criminal Unus the Untouchable. Unus set his gang on Xavier, but they quickly fell under his telepathic control and, when Wicked's friend Freakshow revealed himself, Freakshow dealt with Unus by transforming into a large creature and swallowing him. With the attack over, Wicked and Freakshow were both invited to remain with Xavier so that he could help them with their abilities. After all, he was a teacher. Unaware that Xavier used some telepathic influence on her, Wicked accepted Xavier's invitation. [Excalibur (3rd series) #1]
Taking refuge in the ruins of the once beautiful Hammer Bay, Wicked proved her courage when she discovered the mutated Callisto seemingly attacking Magneto. Wicked set several spirits at Callisto, distracting the Morlock enough to release Magneto from her tentacles. Unfortunately for Wicked, when her spirits are harmed, she felt their pain, and Callisto lashed out, striking several of the ghosts, resulting in Wicked succumbing to their pain. Callisto found Wicked, keeled over outside, and carried her back to the demolished house where Xavier and his growing number of followers began to operate from.
Xavier and Magneto's small group weren't the only faction operating on Genosha. In addition to Unus and his gang, several Genoshan Magistrates were also active, and sought to take control of Genosha for themselves. Wicked and Freakshow were on their own when a group of Magistrates attacked. Having little to no combat training, the young mutants froze in fear, but were fortunately saved by Callisto, who had decided to remain working with Xavier and Magneto. Wicked continued to prove her bravery and, when Callisto was shot at by one of the Magistrates, she sent several spirits to attack the Magistrate.
In the aftermath, Xavier and Magneto were determined to double-down on restoring Genosha and helping those on the island in need. Along with other new additions to the group, Wicked agreed to continue under Xavier's guidance. [Excalibur (3rd series) #2-4]
Wicked happened upon one of her new associates, Shola Inkose, who had collapsed in the rain after literally trying to run from his problems. With dozens of spirits at her side, Wicked sought to help Shola, but found herself attacked by several trolls, who injected her and Shola with nanites. Unconscious, Wicked's spirits disappeared without her to give them form. The trolls were under the command of a pirate-esque scavenger called Stripmine, who had come to Genosha with the intention of plundering its remaining resources, including DNA of any useful mutants. Wicked, Shola, Xavier, Magneto and Callisto all found themselves captives of Stripmine, who subdued their powers with strange necklaces that placed them in a dream-like state, which revealed their deepest desires. Wicked's dream saw her being cared for by a strange, beastly figure with gray fur and large clawed hands, who gave her a beast-like doll as she slept and told her that she was a special child.
The mutants were freed from the dream-states when Shola's powers reacted with the necklace. 
However, Wicked appeared quite traumatized by the ordeal and was left in Magneto's care while the others escaped to deal to the looters and trolls. Wicked couldn't understand why Magneto was being so kind to her, especially when she couldn't do anything to help everyone else. [Excalibur (3rd series) #5-7]
[Note: The face of the beast-like creature shown in Wicked's dream is not depicted on panel. However, the creature looks remarkably like the Dark Beast – and it's probably no coincidence that the Dark Beast himself showed up at the end of the issue, where the dream panel was shown. The significance of the dream was never explored, however, as it was probably a longer-term storyline that Chris Claremont intended to address in a future issue, only for the Excalibur series to be cancelled prematurely with the House of M event. Despite Wicked appearing post House of M, no writer has yet picked up on this thread]
As the mutants began to adjust to life on the ruined Genosha, they also started to explore the ruins and knock down uninhabitable buildings. As part of this process, Wicked used her powers by sending the spirits to search the ruins for anything useful. When the Genoshan Magistrates were slaughtered, Wicked sent as many spirits as possible to search the catacombs of Genosha to find who, or what, was responsible. Unfortunately, the diabolical being known as the Sugar Man was responsible for slaughtering the Magistrates. As one of Wicked's spirits closed in on him, he lashed out, attacking the spirit and causing a violent feedback to take Wicked out. Callisto apologized to Wicked for putting her in this position, but Wicked offered to continue to try to use her spirits to keep watch as Callisto explored the catacombs.
The plans to rebuild Genosha were soon disrupted when Magneto brought the Scarlet Witch to Genosha after a devastating event in which she suffered a nervous breakdown. He and Xavier subsequently began devoting their time to the care of the Scarlet Witch, leaving Wicked and the other mutants with little guidance. While some of the mutants embarked on a rescue mission in an African nation, Wicked remained in Genosha, with hundreds of spirits around her, keeping watch over Magneto. [Excalibur (3rd series) #8-10, 12]
Unfortunately, Xavier and Magneto's efforts were fruitless, as the Scarlet Witch temporarily re-wrote reality and, when that reality was destroyed, she used her power to render more than 98% of the world's mutant population powerless, an event dubbed M-Day. Like the other remaining mutants on Genosha, Wicked found herself powerless. Apparently, those still on Genosha banded together and continued to live among the ruins.
Surprisingly, Quicksilver arrived on Genosha after stealing the Terrigen Mists from the Inhumans upon discovering that it could be used to restore mutant abilities. In an attempt to make amends 
for what his sister did, Quicksilver offered Wicked and the other mutants a chance to have their powers returned to them. However, Quicksilver was unaware of the dangers that this posed to the mutants. Wicked was the first of the group to inhale the Terrigen Mists and was delighted when the spirits returned to her. One side-effect of the Terrigen Mists being used to re-power mutants, however, was an instability with their powers, which Wicked soon discovered when the spirits of her vengeful parents materialized. Having not summoned her parents, Wicked was shocked and unprepared for their return. However, she was able to implore them to vanish.
It was then that Magneto appeared with an injured Callisto, who was suffering from having her 
powers returned by the Terrigen Mists. Magneto tried to get Quicksilver to tell the mutants that he had poisoned them, but Quicksilver fled after a brief skirmish with his father. Magneto wasn't the only one looking for Quicksilver, and the Inhuman Royal Family soon arrived, after tracking Quicksilver and their stolen Terrigen Mists to the devastated island. When Wicked and the other mutants were located by the Inhumans, a fight broke out, and Wicked used her newly returned spirits to battle Crystal. The fight didn't last long, and eventually the Inhumans were confronted by General Lazer of the Office of National Emergency, who had also been searching for Quicksilver. When the mutants' powers began 
acting strangely thanks to the instability of the Terrigen Mists, Wicked and the others agreed to accompany Lazer to the United States for treatment, with Wicked deciding that there was nothing for them on Genosha anymore. Before she departed, Wicked promised Magneto that, as Genosha was her home, one day she would return. [Son of M #5-6]
In unrevealed circumstances, Wicked's powers were somehow restored. It's possible that she eventually returned to Genosha of her own volition, or she accompanied Kitty Pryde to Genosha to help Kitty celebrate Hanukkah and summon the spirit of Kitty's deceased father, Carmen, to help Kitty with this celebration. [Merry X-Men Holiday Special #1]
Wicked apparently left a lasting impression on Kitty (now Kate) Pryde, and when Kate devised a plan to use the fallen nation of Genosha to give birth to the ancient mutant civilization called Threshold, she needed Wicked as part of the mutant “circuit” to activate that rebirth. Once again, Wicked summoned Carmen Pryde, who acted as a guide for Kate with her plans, while the spirits 
that Wicked summoned acted as blueprints for the reborn civilization. Kate's plan was a success and Threshold was indeed reborn on Genosha. Apparently, Wicked resides on Genosha, rather than the mutant nation of Krakoa, as she was not seen celebrating with Kate and the other mutants who formed the “mutant circuit” and Kate's Marauders team back on Krakoa. [Marauders (2nd series) #11-12]
When a small town in Milford, New Hampshire, was devastated in an attack from Orchis, which was blamed on mutants, Wicked assisted a large Krakoan Response Team who set about rescuing civilians and rebuilding the town. Naturally, Wicked's powers lent her to a very specific and important task by connecting the spirits of the dead with their loved ones who were unable to say goodbye in this hateful and senseless attack. She was also seen counseling the dead in a “group therapy” session. [X-Men: Before the Fall – Mutant First Strike #1]
Assuming Wicked still resides on Genosha, she presumably was not impacted by Orchis' assault on Krakoa. However, with the mutant nation of Krakoa no longer a safe haven for mutants, only time will tell whether Genosha, and Wicked, may be called upon again to help mutantkind.