The Phoenix Force seemingly had a similar history as its Earth-8649 counterpart. She truly merged with Jean Grey, rather than impersonating her. Phoenix corrupted Grey and the two destroyed a star. Realizing the danger she was to the universe, Jean committed suicide, seemingly ending them both.
Dark Phoenix was later resurrected by Darkseid; however, her form was unstable due to the X-Men attempts stop him. In the ensuring battle, Professor X and Raven psychically weaken Phoenix so that she it is forced to possess the body of Cyclops to survive. Reunion with her former lover returns Phoenix's memory of her life as Jean Grey, and she turns on Darkseid in revenge for his having reawakened her from death. In a mammoth explosion, both Darkseid and Dark Phoenix vanish.