Wanda Maximoff is the daughter of King Magneto and alongside her half-sister Lorna she is the princess of Genosha. She seems to be quite snotty and self-centered and costantly argues with Lorna out of jelousy. When the Exiles went to her reality to overthrow Magneto they fought and knocked her out while their Wanda took her place. During the battle between the Exiles and Magneto, Wanda and all the others from Genosha discovered that it was him that orchestrated Xavier's death, so Magneto was deposed and an enraged Jean Grey killed him.
When the Exiles returned to her reality with the mission to divide the mutants of Genosha Scarlet Witch was planning to execute the council to leave her "royal status" intact but was ambushed again by the Exiles and their Wanda replaced her once again. The Exiles' Wanda then informed Jean Grey that Scott Summers was cheating on her with Emma Frost and all the mutants of Genosha start rioting taking sides with Jean or Emma. Satisfied the Exiles were ready to leave when Emma and Banshee attacked them searching for Wanda and Emma killed her by breaking her neck out of revenge. The Exiles then left not knowing that when Emma arrived Scarlet Witch took the place of The Witch of the Exiles, so Emma killed their Wanda and not her. Once with the Exiles (that still didn't know about the exchange) she decided to remain with them posing as her counterpart seeing what the rest of multiverse has to offer her.
Powers and Abilities
According to the Wanda Maximoff from Earth-8823 she needs to lose some weight and tended to dress quite "slutty". This however was pretty ironic considering that she seemed to be wearing exactly the same outfit as Exiles' Wanda only without the cape.