The Flash is getting ready for its milestone 100th episode, and it's bringing back several characters from past seasons. The 100th episode will see Team Flash taking a trip back through their past for clues on how to defeat Cicada in the present. (Because what's an episode of The Flash without some time travel?) They will be visiting some of the greatest hits, toughest battles, and biggest foes from The Flash's past four seasons.
Along for the ride is Nora West-Allen, who will be seeing the events of her parents' past firsthand. Hopefully this will help her realize the hard choices they've had to make and how it affects their future decisions, especially after her dealing with her father putting his life on the line to save others in The Flash's most recent episode, "O Come, All Ye Thankful."
While not much else is known about the plot of The Flash's 100th episode, if it's anything like Arrow's 100th episode, then fans are sure to be in for a number of surprises, cameos, and emotional moments. However, here are the characters that are known to be making an appearance in The Flash season 5 episode 8, "What's Past is Prologue."
Team Flash Members Returning for The Flash 100th Episode
Of course The Flash's 100th episode cannot take place without the characters who have helped the show reach this point. Original cast members Barry Allen, Iris West-Allen, Cisco Ramon, and Caitlin Snow (and perhaps even Snow's alter-ego Killer Frost) will be joined by Ralph Dibny, Nora West-Allen, and Sherloque Wells for the big event. Sadly, one original cast member who probably will not feature in the episode is Jesse L. Martin as Detective Joe West, who's still on medical leave from The Flash.
They've been sure to mention him in previous episodes, so hopefully the trend continues, especially because of the important role Joe has always played in Barry's story. While no past Team Flash cast members such as Julian Albert, Wally West, or even Ronnie Raymond have been confirmed to appear in The Flash 100th episode, with the time travel aspect, anything is possible.
Cicada is Returning for The Flash 100th Episode
The whole reason for Barry and Nora's time travel excursions in The Flash season 5 is Cicada. Now that the team knows Cicada's real identity, they're one step closer to figuring out how to stop him and his metahuman power-dampening dagger.
While The Flash's 100th episode is meant to bring back past characters in order to celebrate the show's long-running streak on television, it still very much continues the ongoing story. According to the episode's synopsis says the team needs to gather "key necessities" from the past, whatever those may be. But it makes sense they need to look to the past since the future has been changed due to Nora's arrival.
Eobard Thawne/Reverse Flash is Returning for The Flash 100th Episode
The Flash's 100th episode trailer (via YouTube) shows that traveling back in time will put Barry Allen face to face with The Flash TV show's previous main villains, including the villain that started it all: Eobard Thawne (from the looks of it, he's still disguised as Harrison Wells). Thawne betrayed Barry in The Flash season 1; he posed as a mentor and then admitted he was the one who killed Barry's mother, Nora Allen.
Even though Barry attempted to stop Thawne from murdering his mother, the creation of the Flashpoint timeline would've resulted in the end of the world. And so, Barry needed to allow Thawne to kill his mother in order to protect the timeline and save the world, and that's something he may have to relive once more... with his daughter. Thawne's presence in The Flash's 100th episode also means Tom Cavanaugh will be pulling triple duty, acting as both Sherloque and Thawne, as well as directing.