It's a bit complicated. Jean Grey's fate varies depending on the comic storyline and continuity. Sometimes she's dead, but often there are plot devices that bring her back.
Well, clearly Jean Grey is one of the main characters. And then there's the Original Character (OC). Since it's an OC A14, this particular OC is going to be a central figure. There might also be other X - Men characters like Cyclops, Wolverine or Storm who could be involved, as they are often part of Jean Grey's storylines in the X - Men universe.
One of the best Jean Grey stories is 'The Dark Phoenix Saga'. It's a classic that shows Jean's struggle with the powerful and dangerous Phoenix Force. Her transformation into the Dark Phoenix and the resulting chaos is both thrilling and tragic.
Well, Jean Grey's death in the comics has multiple scenarios. One common cause was her inability to control her immense psychic powers, which led to her demise. Another time, she might have given her life to protect the world or her fellow mutants.