The history of this incarnation of Magik presumably mirrors that of her Earth-616 counterpart, up to the choice to return to Earth.
When the X-Men and New Mutants were to decide to stay in Asgard or return to Earth, Magik, as the new Enchantress, felt that she belonged there, and consequently decided to stay.
She went to inhabit Amora's castle. When war came to Asgard, she summoned Cannonball who had his father-in-law Eitri the Dwarf King to assemble an army and come to Asgard's help.
She then brought the fight directly to Karnilla, the Norn Queen, until Balder convinced Karnilla to stop her attacks, offering to be her king.
As Hela was destroyed, Mirage ruled the kingdom of Hel, at last at peace with Asgard, with Magik serving as emissary between the two kingdoms.
Powers and Abilities
Presumably those of the Magik of Earth-616, possibly completed and/or enhanced by Asgardian magic. Those powers were shown to include:
A tiara, possibly magical.
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