The Phoenix
In 2006’s X-Men: The Last Stand, one of the main antagonists was actually Jean Grey – a character who had previously been allied to the X-Men and the forces of good – when an alternate side of her personality took over her, making her more powerful and more evil.
That alternate personality was called the Phoenix – an entity that, in the comic books, is something completely different and not merely an alter-ego of Jean Grey.
It’s a cosmic force of nature that, when living within a host, grants it incredible psionic powers and augments the host’s existing powers to incredible levels. Fans of the X-Men comic books would really like to see that version in the movie – and it’s a logical progression to use it after Apocalypse, as very few characters could follow him without being underwhelming.
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