The Flash Series Finale: Making Sense of the Show’s Convoluted Ending

Warning: this article contains full spoilers for The Flash: Season 9!

The Flash has been on the air for almost a full decade now. To say the series has grown a little convoluted over time would be putting it mildly. Each new season has introduced more speedster villains, added new wrinkles to the Speed Force and shaken up the show’s constantly evolving supporting cast. Lapsed Flash viewers who have decided to tune into the series finale may scarcely recognize the series as it exists now.

Hopefully, we can lend a helping hand there. Let’s break down everything that happens in The Flash: Season 9’s finale and how it all builds on the series’ increasingly convoluted mythology. We’ll even explain those three new speedsters who make their debut in the final scene.

The Return of Eddie Thawne and the Negative Speed Force

The Flash culminates in one final, epic clash between Grant Gustin’s Barry Allen and the Negative Speed Force, the dark antithesis of the energy source that grants Barry his speed. While the concept of the Negative Speed Force has technically existed since the beginning of the series (it was the source of Reverse-Flash’s power in Season 1), the series has only really started to delve into the concept in more recent seasons. We now know there are four fundamental Forces in the Arrowverse – the Speed Force, the Strength Force, the Still Force and the Sage Force. Each Force also has its negative equivalent.

The introduction of these other Forces has definitely complicated the mythology fueling the series over the last few seasons. But all you really need to know is that the Negative Speed Force has been searching for an avatar to oppose Team Flash and help it destroy the Speed Force, allowing it to grow unchecked. In the climactic four-part storyline “A Better World,” that avatar is none other than Rick Cosnett’s Eddie Thawne.

Here The Flash circles back to Season 1, when Cosnett was still a series regular. Season 1 culminates in Eddie’s choice to shoot himself and end his family bloodline, thus ensuring his descendant, Tom Cavanagh’s Eobard Thawne, is never born and never threatens the world. The Negative Speed Force has plucked Eddie out of 2014 and is tempting him with the promise of recreating the life he gave up. If Eddie becomes the Negative Speed Force’s avatar, dubbed Cobalt Blue, he can kill Barry and create a new timeline where he is Central City’s favorite son.

As a sidebar, Cobalt Blue is another speedster villain drawn from the Flash comics, though as with many of his fellow speedsters, the series is only loosely adapting the source material. The original Cobalt Blue is actually Barry’s long-lost twin brother who is adopted by the Thawnes and grows up to hold a powerful grudge against Barry.

The series finale features Cobalt Blue forming an alliance with all the major speedster villains of previous seasons – Reverse-Flash, Savitar, Teddy Sears’ Zoom, and Karan Oberoi’s Godspeed. Reverse-Flash alone has become an incredibly convoluted villain over the course of nine seasons, given the number of times he’s apparently died and returned again. Time travel has a nasty habit of making everything more confusing. Season 8 seemed to finally close the door on the Flash/Reverse-Flash rivalry, but Season 9 has managed to bring Thawne back on more than one occasion anyway. In this case, this is seemingly a version of Thawne pulled from right before his defeat and destruction in the Season 1 finale, hence why he’s played by Tom Cavanagh rather than Matt Letscher. 

Season 8 seemed to finally close the door on the Flash/Reverse-Flash rivalry, but Season 9 has managed to bring Thawne back on more than one occasion anyway.

As we see, Eddie’s “legion” is a short-lived alliance, and Flash ultimately confronts Cobalt Blue inside the Negative Speed Force as he gathers a potentially lethal amount of energy. As is so often the case on this show, Barry uses his empathy and compassion to break through where his speed fails. He appeals to Eddie’s inner goodness and allows his old friend to overcome the Negative Speed Force’s twisted influence. 

This allows Barry to finally break the cycle of death and destruction that’s fueled the series since Season 1. Building on what Danielle Panabaker’s Khione tells him about “the natural order of things,” Barry comes to understand that the two Speed Forces don’t have to exist in eternal conflict, but can coexist as two sides of the same coin. As the series closes, Eddie is still Cobalt Blue and the avatar of the Negative Speed Force, but he’s no longer necessarily Barry’s enemy. He’s been given a second chance at being a hero. It’s simply an open question as to whether he’s able to make the most of that chance and if the two Speed Forces will continue to coexist in cosmic harmony.

Khione or Frost? What’s the Deal With Caitlin Snow?

Reverse-Flash may be the most convoluted character in the Arrowverse, but Danielle Panabaker’s three Flash roles aren’t far behind. Fans who haven’t watched The Flash since its early seasons may not know what to make of Panabaker in the finale, as she’s no longer playing Caitlin Snow, but rather a completely different yet physically identical character called Khione.

The TL;DR for Caitlin these days is that she discovered the existence of an alternate personality in her mind dubbed Frost. That personality has existed since childhood. There was a period where the two personalities alternated control of Caitlin’s body, but after a clash with Mirror Monarch in Season 7, Frost was given her own body. Caitlin and Frost existed as twin sisters of sorts, up until Frost’s death in Season 8. Caitlin built a machine to try and resurrect Frost’s consciousness, only to wind up erasing her own mind and replacing it with a new personality, Khione.

That’s been the basis of Khione’s ongoing arc in Season 9, as she comes to terms with effectively being a newly born human inside an adult body. Khione has discovered her primal connection to the natural world. And thanks to “A New World,” now we know Khione is a literal nature goddess with all the fantastical powers that come with the job.

Khione finally embraces her role in the Arrowverse and ascends as a full goddess in the series finale. But she leaves Team Flash with a parting gift. Once she vacates the body of Caitlin Snow, Caitlin’s mind is able to resume control. Caitlin is effectively resurrected in the wake of Khione’s departure. The Frost side of her mind is apparently still dead, but it’s still a happy development for Team Flash in general and her old lover, Jon Cor’s Mark Blaine, in particular.   

Who Are the Arrowverse’s New Speedsters?

While we see Team Flash celebrate their victory against the Negative Speed Force and the birth of baby Nora in the finale, that’s not where the series ends. The closing moments of the finale see Barry venture back out into Central City and call down the Speed Force’s lightning. He decides the time has come to share his incredible powers with the world, transforming three ordinary humans into brand-new speedsters. Think of it like the Shazam movies, where Zachary Levi’s Shazam bestows a portion of his powers on his foster siblings. 

As you might expect, all three of these speedsters are based on characters from the comics. Piper Curda’s Avery Ho is a character who previously popped up in a pair of Season 8 episodes, including one where she bonded with Barry’s time-displaced son, Bart (Jordan Fisher). In the comics, Avery is one of several Central City residents who gains speed powers after a Speed Force Storm strikes the city. She eventually becomes China’s designated Flash and helps form the Justice League of China.

Trevor Carroll’s Max Mercury is a character with a long and venerable DC history. Originally called Quicksilver (decades before Marvel’s Quicksilver raced onto the scene), Max Mercury dates all the way back to 1940’s National Comics #5. His modernized origin story revealed that Max was originally a scout in the US Cavalry in the 19th Century, before rejecting orders to slaughter an Indiana tribe. An Indian shaman granted Max the power of incredible speed, which he used to become a superhero and, eventually, a mentor to Bart Allen.

The Arrowverse has obviously done some major tweaking to that origin story. This version of Max doesn’t hail from the 1800’s, and he appears to be an American Indian himself. Presumably, this is the show’s way of avoiding the white savior trope while still acknowledging Max Mercury’s link to American Indian mythology.

Finally, there’s Hana Destiny Huggins’ Jess Chambers. Jess is a relatively recent addition to the DC Comics library, having debuted in 2021’s Generations: Shattered #1. They go by the codename Kid Quick and use a special equation (3X2(9YZ)4A) to access the Speed Force. Kid Quick is also notable for being a relative of the JSA’s Jesse Quick and one of DC’s first nonbinary heroes.

Were DC to continue The Flash in some form or another, we’d no doubt see Barry begin to mentor these three heroes and further build on his superhero legacy. However, there’s no indication that DC will be continuing The Flash or any other Arrowverse series now that The CW has canceled these shows and pivoted in a less superhero-driven direction. The Flash is the last of the Arrowverse to be canceled. Technically, Superman & Lois and Gotham Knights still remain, but neither is part of the same universe as The Flash, and the outlook for both shows is grim.

There’s no indication that DC will be continuing The Flash or any other Arrowverse series now that The CW has canceled these shows and pivoted in a less superhero-driven direction.

It’s always possible DC will revisit the Arrowverse in comic book form, as they have with past projects like The Flash: Season Zero and Arrow: The Dark Archer. But we wouldn’t hold our breath for a full-blown The Flash: Season 10. Even the decision to expand the series to nine seasons came relatively late in the production of Season 8, with showrunner Eric Wallace revealing the Season 8 finale had to be rewritten to set up these final 13 episodes. The Season 9 finale may leave plenty of doors open for Barry and his friends, but that doesn’t mean there was ever an intention of continuing the story beyond this point.

And maybe that’s for the best. As big and weird and often confusing as The Flash’s mythology has become over the years, there’s a lot to be said for knowing when to call it quits. And who knows, maybe we’ll see Gustin’s Barry cameo in the upcoming Flash movie, the same way Ezra Miller’s Barry stopped by during Crisis on Infinite Earths. That would be one way of reminding viewers that the Arrowverse’s legacy lives on, even as The Flash closes a door on this era of DC’s TV lineup. 

For more on DC’s cinematic future, brush up on every DC movie and show in development.

Jesse is a mild-mannered staff writer for IGN. Allow him to lend a machete to your intellectual thicket by following @jschedeen on Twitter.