'Legends of Tomorrow': Who Is Jesse Quick?

Fan-favorite John Constantine returns to help the team deal with a Mallus-posessed Sara tonight on Legends of Tomorrow, but his won't be the only familiar face for fans of The CW's Arrowverse.

Somewhere in tonight's episode fans will get some form of reunion between Wally West (Keiynan Lonsdale) and Jesse Quick (Violett Beane), Earth-2's speedster who fans last saw helping Barry Allen (Grant Gustin) stop a nuclear bomb from exploding on The Flash. But who is Jesse Quick and why is her seeing Wally so important? Here's what you need to know.

In comics, Jesse Quick's real name is Jesse Chambers. First appearing in Justice Society of America Vol. 2 #1 in 1992, she's the daughter of Golden Age heroes Johnny Quick and Liberty Belle and inherited both of her parents' powers meaning that she isn't just a speedster, but she has superhuman strength and can fly, too. A member of the Justice Society of America, Jesse eventually met Wally West who was operating as the Flash. Wally asked her to take up the mantle of the Flash should something happen to him, but it was really part of an elaborate plan to force Bart Allen/Impulse, to take the role instead. Jesse felt betrayed by this, though she did later save Wally's life. She later takes up her mother's mantle, Liberty Belle, with the JSA and marries a fellow second-generation hero, Rick Tyler/Hourman.

The Arrowverse's take on Jesse is quite a bit different. First appearing during the second season of The Flash, she is Jesse Chambers Wells, nicknamed Jesse Quick by her father, Earth-2's Harrison Wells (Tom Cavanagh). Jesse is a brilliant young college student but had no powers and is captured by the speedster villain Zoom. She is eventually rescued when her father, along with Killer Frost, Earth-2's Iris West, and Barry Allen arrive and help her escape to Earth-1. From there Jesse had a bit of an adjustment period trying to deal with her new life on an unfamiliar Earth. She quickly made friends with Wally West, who himself was trying to fit in as the long-lost brother of Iris West.

Jesse would eventually gain her speedster powers thanks to being hit by a wave of dark matter created when Team Flash recreated the S.T.A.R. Labs accelerator explosion that originally gave Barry his powers -- necessary as Zoom had taken Barry's powers. Jesse's relationship with Wally also took a different turn, with the pair dating after initially deeming it improbably due to her home being on a different earth. And speaking of that other Earth, Jesse and her father do eventually go back to Earth-2. Jesse also spends some time on Earth-3, stepping in as that world's Flash while its real hero, Jay Garrick, sacrificed himself in the Speed Force. When Jay was able to resume his duties on Earth-3 after the defeat of Savitar, Jesse became the Flash of Earth-2, a role that ultimately caused a rift between her and her father as well as her breakup with Wally via a device called a Breakup Cube. Think of it like being dumped by text message only with hologram.

Considering the end of her relationship with Wally, it will be interesting to see how Jesse and the newest Legend get along in tonight's episode.

"There's a bit of [Jesse feeling like she owed Wally a chance to see her again]," Beane explained during a recent interview with TV Line. "You see Wally and Jesse together in a room, and things are not what you expect them to be. And... that's about all I can say! [Laughs] It's going to be cool and, I think, pretty surprising for the audience."

Legends of Tomorrow airs Mondays at 8/7c on The CW.