The Flash features numerous superheroes from its eponymous speedster, to Sasha Calle's Supergirl, to Michael Keaton's returning Batman, and more. But there's also a human element to the film, embodied primarily in Kiersey Clemons Iris West, the love interest of Ezra Miller's Barry Allen/Flash.
Iris and Barry's relationship is central to the movie, just like in Barry's comic book adventures. In comics, Iris and Barry have been together since Barry's introduction as the Flash in 1956's Showcase #4, by writer Robert Kanigher and artist Carmine Infantino.
Barry and Iris formed the first modern example of a superhero couple, with Iris often criticizing Barry for running late to their dates, while Barry hid his superhero identity from her, all while Iris uses her skills as an investigative journalist to try and unpack Barry's secrets.
This relationship dynamic eventually evolved even further when Iris' nephew Wally West became Barry's sidekick Kid Flash, which Barry and Wally also hid from Iris.
However, Iris finally learned that Barry was the Flash when he talked in his sleep on their wedding night - a somewhat silly Silver Age plot contrivance - with Iris continuing to hide her knowledge of Barry's secret identity from him until their first anniversary.
From here, the happy couples' timeline takes some mind bending twists and turns which are a bit hard to explain. First, it's revealed that Iris West is actually from the far-flung future of the 30th century, though she was raised in the present day. This reveal becomes important later on - but not before tragedy strikes.
In 1979's The Flash #175, Iris is murdered by Professor Zoom - the original Reverse Flash. This leads to the landmark 1983 story 'The Trial of the Flash' in which Barry Allen kills Zoom to prevent him from murdering his new girlfriend Fiona Webb. That epic story, written by Carey Bates with art from Carmine Infantino, lasted from Flash #323 until Flash #350, the final issue of the series before Barry's death in the story 'Crisis on Infinite Earths'.
In Flash #350, Barry is reunited with Iris in the 30th century, where she's been resurrected through complicated comic book means. There in the future, Barry and Iris become the parents of the superheroes known as the Tornado Twins, who are also members of the Legion of Super-Heroes.
Sadly, Barry would die soon after in the course of saving reality from the Anti-Monitor in Crisis on Infinite Earths #8, a story which also wound up rebooting much of the DC timeline. After Barry's death, Wally West, the former Kid Flash, stepped up into the role of the Flash, staying DC's main Flash for decades after.
Barry eventually returned just before the 2011 story 'Flashpoint', which is partially adapted into the film The Flash. And when 'Flashpoint' rebooted the DC Universe again into the 'New 52' era, Iris West was also restored.
But the restored Iris and Barry didn't remember their previous lives together thanks to the quirks of how the DC Universe was rebooted. In the years since, they've begun to regain their memories and rekindle their romance, even as Barry has become part of a group of Multiversal protectors known as the Totality.
Though The Flash doesn't exactly go into Iris West's 30th century origins, her relationship with Barry Allen does feature closely in the film, doing justice to the couple's 67 year comic book history.
Iris West features in some of the best Flash stories of all time.
