(No, that's not a misspelling - that's how Marvel is spelling their newest X-Men team. Not in the traditional spelling of 'Legionnaires' with two 'n's, and not connected to DC's Legion of Super-Heroes, who sometimes call their members Legionnaires.)
Marvel's Legionaires are introduced in the final pages of X-Men: The Onslaught Revelation, as the name of an informal group of heroes organized during the battle with Onslaught.
"Mutant cops - with my brain as the precinct," says the team's namesake, Legion.
The name is chosen by Nightcrawler, after rejecting Legion's suggestions of Peacekeepers, Shepherds, and Mutant Jedi - but describes the Legionaires as being different from the police.
"It's not police," says Nightcrawler. "We must defend what unites us, not punish the growing pains."
According to a "coming soon" advertisement after the story ends, the Legionaires line-up is comprised of Nightcrawler, Pixie, Juggernaut, ForgetMeNot, Doctor Nemesis, and Blindfold.
"We keep the peace. We keep the law. We keep the Spark," reads Marvel's ad for the new team.
As defined by Nightcrawler, the Spark is a philosophical-but-not-religious path of living birthed out of the formation of the mutant nation of Krakoa.
The team will be based inside Legion's proverbial head - and that's not a metaphor. As a multi-powered mutant, Legion has at times organized his mind to be a functioning pocket universe. Using Krakoan technology and a little bit of inspiration, Legion has set it up as a permanent locale that will be accessible to mutants via a Krakoan portal he has seeded within his own psyche. He's nicknamed the place 'The House of L.'
Marvel hasn't made it clear how or where the Legionaires will be "coming soon", but it's possible they'll get their own Legionaires title. They could also theoretically appear in a second volume of Way of X, should that come to pass, or as part of another, totally different book.
Back when the surprise ending of Way of X and the X-Men: The Onslaught Revelation one-shot was announced, writer Simon Spurrier told ComicBook.com that his story would continue - but wouldn't elaborate on the shape of what comes next.
"There are some really big X-centric things coming down the pipe, which significantly muddy the waters of what you might think of as endings and beginnings," Spurrier said. "We're having a lot of fun rethinking the ways that shared-universe stories can be told. In practice, what that means is that when Way of X ends, it's absolutely not the end of the story. In TV terms, Way of X is season 1, and The Onslaught Revelation is the big season finale.
"Season 2? Well. Season 2 is something else altogether…" Spurrier hinted.
The Legionaires are the latest in a long line of X-Men teams across Marvel history.