The Legends of Tomorrow season 1 finale introduced a major group in the history of comic books. Who are they and what does it mean moving forward?

In the final moments of “Legendary,” a man calling himself Rex Tyler appeared in a time ship, telling the Legends not to get onto the Waverider because they would die. He reveals that he is a member of the Justice Society of America.

Most fans will be aware of the Justice League of America, a team of DC Comics’ elite heroes. There is an upcoming film in the works that will feature Batman, Superman, Wonder Woman, The Flash, Aquaman and Cyborg. But just who is the Justice Society?

In fact, the JSA is the precursor of the JLA. More than that, the JSA is the first superhero team ever published in comic books. The JSA first appeared in All-Star Comics #3, published in December 1940, and its founding members were Doctor Fate, Hourman, the Spectre, the Sandman, the Atom, the Flash, Green Lantern, and Hawkman. The JSA served as a team of elite fighters protecting America’s home front during the war.

Through the years, other noteworthy members of the JSA have included Black Canary, Mr. Terrific, Red Tornado, Power Girl, Hawkgirl, Starman, Jesse Quick, Citizen Steel, Wildcat and Earth-2 versions of numerous characters including Huntress, Wonder Woman and Robin.

So, what does the JSA’s existence in the Arrow-verse mean?

Legends EP Marc Guggenheim tells THR of Rex Tyler, aka Hourman, “With his final words in the finale, he planted a pretty deep flag about where we’re headed in season 2, which is not just introducing Hourman but introducing his teammates in the Justice Society of America. For comic book fans, everyone knows the Justice Society is really the precursor to the Justice League, so it’s a pretty big move in our DC universe here on TV.”

Additionally, Guggenheim tells EW, “Phil Klemmer, Geoff Johns, Dan Evans, and I sat down in a room at DC with a list, and it’s a long list, of the members of the JSA. One of the more fun afternoons I’ve had recently is sitting down and actually composing our JSA lineup, our perfect JSA lineup. That was a blast to do.”

We do know, however, that Legends of Tomorrow is casting two new series regulars. The new male character’s grandfather was a World War II herol he’s used a “Han Solo-like facade” to make this insecurity, but then he develops superpowers, which allows him to live up to his grandfather’s legacy.

Meanwhile, the new female character is a “member of an elite paramilitary team living in the 1940s.” This character is African-American, so she must work twice as hard as other soldiers to overcome her race and gender in the eyes of other soldiers.

Guggenheim adds that season 2 will see the Legends taking on a new role. “Because the Time Masters are essentially gone and the Legends have destroyed the Oculus, that all means that someone else has to do the job of the Time Masters. Our Legends take that on as their new responsibility. It’s sort of like, you break it, you buy it.”

“That’s really exciting to us, that our team of Legends, our misfits, are going to be responsible for the preservation of the timeline and protection of history,” he says. “As we’ve seen, our team, our guys are not always the most responsible people around so maybe time has got some new troubles. But it will provide a lot of fodder, a lot of fun story for season 2.”

As for the Legends’ nemesis in season 2, Guggenheim won’t say who it is but teases, “Vandal Savage looks like a walk in the park compared to what the Legends will be facing. This will be a much, much bigger threat,” adding, “It’s going to be way bigger than what you can even imagine, I can guarantee it.”

Are you looking forward to the JSA on ‘Legends of Tomorrow’?