WARNING: The following article contains spoilers for The Flash Season 6, Episode 15, "The Exorcism of Nash Wells."
On The Flash, Eobard Thawne has recently returned to plague the life of Barry Allen. Although he was missing for a while, the character made a surprise return after the conclusion of the "Crisis on Infinite Earths" crossover. During the event, the multiverse was destroyed, and a new Earth-Prime was created. As a result, all alternate versions of Harrison Wells found themselves inside Nash Wells. Since Thawne was once a copy of Wells, he too has found himself inside Nash -- and he quickly made his presence known.
In "The Exorcism of Nash Wells," Team Flash was able to get Thawne out of Nash for good. As for the Reverse-Flash, he was essentially converted into energy and set loose in the atmosphere. The supervillain may be gone for now, but he is certainly not dead. Now, he is free to return looking like anyone, making this the perfect opportunity to see the character return as Eddie Thawne.
Eddie Thawne was one of the main characters of The Flash in Season 1. Played by Rick Cosnett, the character was a police detective and partner of Joe West in the CCPD. On top of that, Eddie was Iris' fiancé and a friend of Barry Allen who would eventually learn about his secret identity as the Scarlet Speedster. Given his name, it was clear the character had some connection to Eobard Thawne, aka the Reverse-Flash. At the time, fan theories event speculated that Eddie himself was actually the man in the yellow suit. However, that didn't turn out to be the case.
In truth, Eddie was Eobard Thawne's ancestor. When he learned that crucial fact, Eddie made the ultimate sacrifice to save his friends: he took his own life, thus erasing his future family line from existence. Therefore, Reverse-Flash was erased from the timeline, and Eddie's presence on the series, unfortunately, ended.
But now is the perfect time to bring the character back. After being exorcised from Nash Wells, the Reverse-Flash's energy is out in the world in the form of lightning. It may take him some time, but he will eventually figure out how to gain a new body -- either by finding another vessel to take control of or by somehow building himself a new body. Since Eobard could, therefore, return looking like anyone, this would be an opportunity to bring Rick Cosnett back in the role of Eddie. This time around, though, the character could finally get his due, by assuming the villainous role he was long rumored to be attached to.
Since "Crisis on Infinite Earths" essentially rewrote all of the Arrowverse's continuity, Eddie could easily be brought back. In this reality, he could have never killed himself. Either that or Reverse-Flash's energy could be able to travel back in time and find him. However it happens, it would make for a fun twist on the series, and a welcome return for longtime fans of The Flash.
What's more, Eddie's return as Reverse-Flash would not only allow Cosnett to shine as the villain, it would be a new way for Thawne to mess with Barry and his friends -- something fans know he loves to do. Before, it was by hiding as a friend. Then, it was by becoming the mentor of Nora West-Allen. And this time around, it would be by taking the face of Iris' deceased boyfriend.
Airing Tuesdays at 8 p.m. ET/PT on The CW, The Flash stars Grant Gustin, Candice Patton, Carlos Valdes, Danielle Panabaker, Tom Cavanagh, Jesse L. Martin, Danielle Nicolet and Hartley Sawyer.