Barry Allen and Iris West-Allen's daughter from the future, XS, will return to Central City for a family reunion in the 150th episode of The Flash.
According to Entertainment Weekly, Jessica Parker Kennedy will return to The Flash for multiple episodes, which include the landmark episode that includes Impulse's Bart Allen (Jordan Fisher), who is her brother who also happens to be from the future.
Kennedy made her debut on The Flash in Season 4, though fans were not aware of her real identity at the time. She played a waitress at Barry and Iris' wedding, and then returned for the Season 4 finale where she told her parents the truth behind her identity. However, one secret Nora hid from Barry was that she was trained by his nemesis, Eobard Thawne, in how to use the Speed Force in her future. Nora/XS was erased from the timeline in the Season 5 finale after Team Flash defeated Cicada and Thawne.
Fisher's portrayal of Bart Allen was announced at the end of March, with the actor appearing as a recurring guest star beginning with Episode 150. The official description for Fisher's Impulse reads, "Bart is the fastest teenager on the planet! But due to Bart's penchant for wildly impulsive behavior, stunned parents Barry and Iris will have their hands full trying to teach their new son patience. But it's a task they'll have to accomplish, in order for their family to work together and stop Team Flash's biggest threat yet!"
The Flash stars Grant Gustin, Candice Patton, Jesse L. Martin, Danielle Panabaker, Carlos Valdes and Tom Cavanagh. The series returns from hiatus Tuesday, May 4 at 8 p.m. ET/PT on The CW.
Source: Entertainment Weekly