'The Flash': Who Is XS?

The mystery of The Flash's "Mystery Girl" was solved at the end of last season, revealing the curious stranger to be none other than Barry and Iris' daughter from the future, Nora -- codenamed XS. Now, as fans get to know more about Nora in tonight's season five premiere, let's take a look at just who XS is in comics and what that could mean for Nora as the season unfolds.

Spoilers for tonight's season five premiere of The Flash, "Nora", below.

When Nora (Jessica Parker Kennedy) crashes the welcome home party for baby Jenna West, she quickly divulges her heroic name, XS, and that it comes from the childhood nickname given to her by Iris (Candice Patton). It turns out it's a derivative of the world "excess" -- as in everything Nora did was in excess. She even has her own heroic costume that's based off of the jacket that Iris wore during her brief stint as a speedster.

Fans of DC Comics will readily recognize both the name XS as well as the costume as belonging to Legion of Super-Heroes member Jenni Ognats. In comics, Jenni is the granddaughter of Barry and Iris Allen in the 30th century. The daughter of Dawn Allen and her husband Jeven Ognats of Aarok, Jenni has no super powers to speak of for most of her life despite much of the rest of her family being speedsters. However, when she is captured by Dominators curious about her lineage. When she sees her father tortured by them, her latent super-speed ignites with Jenni then using it to save her father and escape.

Still new to her powers, Jenni later checks herself into a lab so that she can learn to use her super-speed and other powers, including super stamina and durability. Once she gets comfortable with and learns to control her powers, she's drafted into the Legion of Super-Heroes and becomes a hero in the tradition of her grandfather and mother, both of which died as part of their heroic deeds.

Fans of The Flash speculated before Nora's identity was revealed that the character would be either the show's take on Dawn Allen or Jenni Ognats and it turned out to be a little bit of both, but if the series borrows anything else from the comic book version of XS outside of a code name and costume it may be that family dynamic. Earlier this year, series star Grant Gustin teased that Nora would have a complex relationship with her parents, one that would see them all on different pages.

"We're all on different pages," Gustin said. "We're all in a different headspace about it. Nora's really clingy to Barry and we don't really know why, and a little more distant with Iris."

It will be interesting to see the reasons why Nora's relationships to each parent is so different as The Flash's fifth season plays out.

The Flash airs Tuesdays at 8/7c on The CW.