Millions of years ago, Marvel’s oldest Avengers roamed the planet, apparently along with the very first earthly incarnation of the Phoenix. This time around, fortunately, the X-Men's classic foe isn't a threat to the planet (at least not yet). In fact, this firebrand appears to be a champion of the prehistoric era.

Phoenix and the rest of her primeval Avengers arrive in Marvel Legacy #1, kicking off Marvel's latest fall lineup. Legacy follows Marvel’s “last” big event book, Generations, which teams up every hero with their namesake, including the Hulks and Captain Americas. As part of the event, the House of Ideas will also introduce fans to the planet's first superhero team-up, 1,000,000 BC-style.

Over the last week, Marvel released a string of promos, teasing “Who Are The Avengers Of 1,000,000 BC?” Now, they've announced their archaic crew. In addition to Jean Grey’s old flame, the Phoenix, the team includes prehistoric renderings of Black Panther, Iron Fist, Ghost Rider, as well as Agamotto (the first Sorcerer Supreme), Starbrand, and Odin. Phoenix also received a Clan of the Cave Bear makeover, courtesy of Mike Deodato Jr.

Marvel Legacy #1 arrives in September and introduces readers to the Marvel Universe's first planetary guardians. The event kicks off with a mammoth, 50-page prehistoric adventure, written by The Mighty Thor scribe Jason Aaron and featuring art from Esad Ribic (Secret Wars). According to Editor-in-Chief Axel Alonso, Legacy #1 is the Big Bang, so to speak, of the Marvel Universe:

“Fans are going to witness an all-new look at the Marvel Universe starting at one of the earliest moments in time carried all the way into present day. Not only will this be the catalyst for Marvel evolving and moving forward, but expect it to be the spark that will ignite the industry as a whole.”

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One of the primal universal forces, Phoenix first rose from the pulpy ashes of X-Men #101 (1976), created by Dave Cockrum and Chris Claremont. Typically a lethal defender of evolution, the Phoenix Force is now part of the ever-growing X-Men legacy itself, adapted for comics, TV series, and movies. Adding a deeper, Earth-based connection to this cosmic entity is a perfect introduction for new readers, especially with FOX's Dark Phoenix saga on the way. Long time fans should also find new insight into the complex, primordial character as well.

The Legacy one-shot allows for a lot of curious possibilities for the Phoenix and beyond. Until now, the cosmic entity's earliest known human host was the great ancestor of one-time Excalibur team member Feron. Now, the currently unnamed ancient Jean Gray-lookalike appears to be the oldest human host. As such, watching Aaron develop Phoenix's longtime link to the planet should prove fascinating.

What better way to spark new life into Marvel Legacy than with the Phoenix? One thing’s for sure, with two fiery teammates (Ghost Rider and Phoenix), prehistoric humans won’t need to go on any Promethean crusades.

Next: Marvel’s X-Men Grand Design Comic Explores Mutant History

Marvel Legacy #1 hits shelves on September 27 of 2017.