How The CW's Flash Changes DC's Cobalt Blue's Origin Story

Love it or hate it, "The Flash" has ended on The CW, bringing an end to the Arrowverse that once dominated the network. Barry Allen (Grant Gustin) saved Central City for one final time, with Cobalt Blue becoming The Flash's last on-screen villain. However, the Cobalt Blue audiences saw in the final episodes comes with some changes from his comic-book-counterpart. 

In "The Flash," Eddie Thawne is Cobalt Blue, with Rick Cosnett returning for the show's final season. Cosnett played Thawne in Season 1, serving as a red herring, as many expected the show to reveal him as Season 1's Reverse Flash. While that wasn't the case, Cosnett finally gets to play the villain as Cobalt Blue. 

In the pages of DC Comics, Cobalt Blue's secret identity is Malcolm Thawne, who's only a Thawne by name as he's actually Barry's twin brother. Separated at birth by an alcoholic doctor, Malcolm is raised by the Thawnes, who used blue flame in their con-artist routine. Like most villains, he developed a distinct hatred for Barry, who got to live a better life than him, despite coming from the same parents. He eventually learned to harness the Thawnes' power, becoming Cobalt Blue, facing off against the Flash and Kid Flash, and using his blue fire to steal their speed.

Rick Cosnett's return to "The Flash" was just one of many reunions of the show's final season, including Jessica Parker Kennedy (Nora West-Allen) and Matt Letscher (Reverse-Flash). However, acting opposite Cosnett again left a lasting mark on star Grant Gustin, who really enjoyed what they achieved in the final episodes. 

"Rick is another one that blew me away," Gustin told TVLine regarding returning cast members ahead of "The Flash" series finale. "I mean, we had some really cool scenes the last couple episodes, and he kind of ran the gambit with his performance in the last few. I mean, he got to do some really interesting stuff. There was some really fun stuff for him. It's unlike anything he's done on our show before, and I think, based off conversations I had with him, it was unlike anything he's done in his career."

Gustin said Cosnett's performance in the show's final episode impressed him, refusing to reveal if Eddie would become Cobalt Blue. While he played coy regarding Eddie's fate, we now know that's where the final season took the character, giving fans the fight between Barry and Eddie they've been waiting for since the show's beginning. The four-part finale event saw Eddie accept his powers in the penultimate episode, setting up his turn to villainy in the climactic final episode and paying off the long-running mystery of the blue crystal, which "The Flash" established in its Season 8 finale.