Warning: this article contains spoilers for X-Men #11!
While a majority of the X-Men’s superhero monikers are truly iconic and even more recognizable than their real names, one of the original team members has officially retired their codename for good, as it never proved to be the right fit for this particular mutant hero.
The X-Men made their debut in Marvel Comics with X-Men #1 by Stan Lee and Jack Kirby. Aside from their leader and mentor, Charles Xavier, the original five X-Men were Cyclops, Marvel Girl, Iceman, Beast, and Angel. While the X-Men roster has changed a number of times over the years, these heroes have remained core to the franchise. However, as one hero takes a more starring role in recent comics, they're rejecting their original name as a relic of the past.
In X-Men #11 by Gerry Duggan and Pepe Larraz, the X-Men have traveled to a deep space casino known as Gameworld where someone is encouraging bets on the destruction of Earth. The X-Men use a connection made by Rogue to infiltrate this seedy planet and get to the bottom of the world-ending threat. Jean Grey confronts the assembled aliens with a show of powers, declaring that she will not be used as their plaything. As she absolutely commands the room, Jean states definitely, “I was Marvel Girl. Now I am Jean Grey”.
At the start of this new era of the X-Men franchise - which began with House of X and Powers of X - Jean Grey returned to her original costume and moniker, shedding the years of baggage and control that went with her connection to the Phoenix name. Fans critiqued the move at the time, as Marvel Girl was Jean's teenage title and some read it as a regression of the character, but whether that was the case or not, recent stories have celebrated Jean as a mutant powerhouse and one of Marvel's most important heroes.
Now, Jean has made it known that she will not be called Marvel Girl any longer, officially declaring it a relic of the past. This declaration will make it hard to convincingly resurrect the name in future, as Jean's comments imply that even she sees it as an old identity she's grown beyond. While 'Jean Grey' may be a civilian name, the link to 'grey matter' at least includes some reference to her mind-reading abilities, which 'Marvel Girl' never offered in the slightest.
‘Marvel Girl’ was never a fitting name for Jean Grey even when she was just a teenager during her early days on the X-Men, and now that she is an adult woman with omega-level abilities, the moniker is even less fitting. X-Men officially retires an original team member's codename, leaving Marvel Girl in the past so Jean Grey can flourish.