Death is a strange thing in comics. Not only have some of the most popular characters died at some point in their continuity, but chances are, if they haven’t already, they will eventually be resurrected. But this wasn't always the case; at one point there was even a rule at Marvel that if a character died, they stayed dead. The character most responsible for the erosion of death’s permanency in comics? Jean Grey, and her multiple deaths and resurrections.
Debuting as one of the founding of the X-Men, writers found Jean Grey a hard character to make compelling compared to her teammates, due to how limited her power set was (initially). But when writer Chris Claremont wanted to make the character more interesting, he decided to give Jean the powers of a god. In doing so, he would kill Jean in Uncanny X-Men #100, as she sacrificed herself to save her team, only to be immediately resurrected as the host of a cosmic entity known as the Phoenix. Jean/Phoenix would die again in Uncanny X-Men #137, after killing herself in order to keep the Phoenix from taking control of her body. Unlike the first time, Jean would remain dead for a few years -- which is strange, considering Claremont didn’t even want her to die at the end of the story.
Related: X-Men's Jean Grey Is More Powerful Than The Strongest Inhuman
Originally, Jean Grey was intended to survive the events of the Dark Phoenix Saga, but after destroying a whole planet full of sentient beings in Uncanny X-Men 135, then editor-in-chief Jim Shooter found the character unforgivable. Because of this, Shooter decided that Jean should die for her crimes, despite her not being in control of herself when destroying the alien planet. Eventually, in the mid-’80s, Jean would return to life after revealing that she never died in Uncanny X-Men #100, but was actually put into a bizarre cocoon at the bottom of the ocean as the Phoenix ran around in a copy of her body. This retcon was a means of making Jean an innocent character again in the eyes of Marvel readers and editors while injecting drama within the comics.
Jean would once more during Dark Phoenix Saga could undermine and retcon a beloved storyline in such a lazy fashion gave credence to the idea that death no longer mattered in comics.
Though her deaths are often sacrificial, Jean finds herself in a never-ending cycle of death and life that continues to this very day. As Jean Grey lived and died, other characters such as Superman, Green Arrow, and Elektra would follow in her in dying and being resurrected shortly after. Considering this, it’s almost as if Jean Grey killed the concept of a truly permanent death within the comic book medium.
