The ninth and final season of The Flash is set to become a major crossover event, including several returning characters from across the Arrowverse. After nearly a decade on the air, Grant Gustin's Barry Allen will finally run his last race, essentially bringing an end to the mainline Arrowverse as the final Arrow spinoff that takes place on Earth-Prime. As the season approaches its premiere in early February, more and more news breaks concerning its potential story and litany of guest stars, each of whom is sure to lend their unique talents to help close The Flash out with a bang worthy of its long and celebrated tenure.
As The Flash prepares to fulfill its remaining teases in a thirteen-episode final season, Barry Allen will be joined by more than just his usual friends and family. Seven characters from different corners of the Arrowverse have already been confirmed to join the Flash in his final adventure, including some that haven't been seen for a number of years. The many guest stars offer a ray of hope that The Flash's ninth season will offer a return to form for the series, which has suffered in quality over the last several years, though only time will tell if the final batch of episodes can deliver on all its promises.
Hartley Rathaway/Pied Piper
A remnant of days when the Flash was far more powerful than his villains, Hartley Rathaway, also known as the Pied Piper, will return in the upcoming season of The Flash. Portrayed by Andy Mientus, Hartley first appeared as far back as season 1, where he used his command over sonic frequencies to menace Team Flash. Following various multiversal phenomena, Hartley was retconned as a hero and ally to the Flash, though he hasn't appeared in the series since Season 6. The Pied Piper makes a brief appearance in the first trailer for Season 9, with Barry pleading for his help despite Hartley's claims to have "nothing to live for."
Ramsey Rosso/Bloodwork
The showrunners are finally raising the stakes now that The Flash is ending with season 9, bringing back one of their best villains in Sendhil Ramamurthy's Ramsey Rosso, a.k.a. Bloodwork. This terrifying supervillain has the uncanny ability to control blood, even using his powers to briefly control the Flash himself. Bloodwork has been locked up since his initial rampage in Season 6, but news of his return suggests that he will finally have the chance to get revenge for his defeat at the hands of Team Flash. Details are scarce regarding Rosso's return, but it is sure to be as epic as his initial arc was back in Season 6.
Ryan Wilder/Batwoman
Javicia Leslie is among several Arrowverse alums returning in The Flash's ninth season, with rumors claiming that she will actually be portraying the Batman villain Red Death. Leslie previously portrayed Ryan Wilder, a.k.a. Batwoman, in the second and third seasons of Batwoman, replacing Ruby Rose's Kate Kane prior to the series being canceled. It is unclear whether Leslie's original character will also appear in The Flash Season 9 alongside her evil speedster counterpart, but the mere presence of Red Death should be enough to raise eyebrows regarding the upcoming season's potential storyline. If the Red Death does appear, she could very well be the main villain of the season.
Nia Nal/Dreamer
Supergirl alum Nicole Maines will also be returning for The Flash as Nia Nal, a.k.a. Dreamer, once more fueling rumors of a Dreamer Arrowverse spinoff series. Dreamer, like many characters from Supergirl, has been almost entirely absent from the Arrowverse since the series came to end in late 2021. Her incredible power set is sure to come in handy when paired with the Flash, however, marking the first time that the two characters have teamed up without Supergirl present. Dreamer's featured role in The Flash could still hint at an appearance from Kara or other Supergirl characters, though fans will have to wait to see if this proves true.
John Diggle/Spartan
Continuing his trend of making cameos in a post-Arrow Arrowverse, David Ramsay will once more portray Earth-Prime's John Diggle, a.k.a. Spartan. This confirmation reignites rumors that Diggle will become a Green Lantern following his discovery of a strange green space rock in the Arrow series finale. Diggle has made several appearances on The Flash since the conclusion of his original series, with each cameo furthering his Green Lantern arc. While his most recent appearance seemed to bring this storyline to a halt, with the lantern seemingly destroyed, The Flash's final season may be the Arrowverse's last chance at finally transforming John Diggle into a member of the Green Lantern Corps.
Wally West/Kid Flash
Keiynan Lonsdale is finally returning to The Flash as Wally West after over two years of being absent from the Arrowverse, even missing The Flash's 150th special episode in Season 7. In The Flash's early seasons, West served as Barry's sidekick, known as Kid Flash, but eventually departed the series. While Wally made sporadic appearances in the years that followed, including a short-lived stint on Legends of Tomorrow, he has been largely absent from the Arrowverse for many years. His recently announced appearance in Season 9 gives The Flash one last opportunity to wrap Wally's story up in a satisfying way after years of ignoring the character.
Oliver Queen/Green Arrow
Over three years after his death during the Crisis on Infinite Earths event, Oliver Queen is finally returning to the Arrowverse for one last ride with his old friend, Barry Allen. As the Green Arrow, Oliver kickstarted DC's television success and the Arrowverse, leading to a host of spinoffs, crossovers, and even unrelated series being produced surrounding DC's lesser-known comic book characters. Oliver was last seen after the Crisis, transcending the mortal plane in death and rewriting reality in the process. While Stephen Amell was supposedly finished with the Arrowverse after Oliver's death, the conclusion of The Flash seems a big enough event to warrant his return.
The context of Oliver's return remains unclear, with questions swirling regarding how this might be possible considering the character's death. Regardless of whether Oliver returns in flashbacks, an alternate universe, or if he is somehow reborn, the Green Arrow's presence hints at the Arrowverse's end. With the showrunners bringing back the hero that started it all, it seems appropriate that the Arrowverse finally comes to an end with Oliver Queen's surprise final appearance. Even with the many guest stars that will appear throughout The Flash's final episodes, there is no denying that the most exciting of these is Amell's return as the Arrowverse's premiere hero.
