Polaris

Lorna Dane walked into the X-Men's world in 1968 as a mystery with green hair and magnetic powers, and the question everybody asked was the one she least wanted answered: is she Magneto's daughter? Marvel spent decades dodging it with a hoax origin, a shrug and a retcon before finally confirming what readers had assumed from the start. Polaris built a career on refusing to be defined by it — X-Men fieldwork, a long tangled relationship with Havok, and a level of magnetic control that reaches her father's league on his own terms.

Her story is also one of the most honest depictions of mental illness in superhero comics. Possessed by the Marauder Malice, then standing in the middle of Genosha when the island's entire mutant population was murdered, Lorna came out of it broken in ways the genre usually skips. Peter David's X-Factor Investigations gave her a bipolar diagnosis, medication, relapses and the grinding ordinary work of managing it, without ever suggesting her powers were the illness. She led X-Factor again on Krakoa, which is the whole arc: mystery, then casualty, then the person in charge.

Polaris arrived at the tail end of the original X-Men's run, created by Arnold Drake and Don Heck, and immediately became a franchise loose end — too powerful to ignore, too complicated to resolve. Claremont used her as a horror engine through the Malice possession; Peter David gave her the best writing of her life across two separate X-Factor runs; the early 2000s finally confirmed the Magneto parentage outright. Her Krakoa-era X-Factor leadership and Emma Dumont's performance on 2017's The Gifted work from the same premise: Lorna is at her strongest when she is responsible for other people.