The Waverider has suddenly found itself with a couple of empty seats, but it doesn't look like the Legends of Tomorrow will be down a team member for very long.

Tuesday's fall finale of Legends confirmed the exits of both Martin Stein (Victor Garber) and Jefferson Jackson (Franz Drameh), the two characters who combine to create Firestorm. Stein was killed by Nazis in Crisis on Earth-X and Jax decided he couldn't continue without his partner. Suddenly, there is a massive hole to fill on the time-travelling team, and fans are wondering who could possibly fill it.

According to executive producer Marc Guggenheim, "a previously established character from the Arrowverse" will be stepping in to replace Firestorm on Legends.

The conversation came about when we asked the producer about Ray's introduction, and whether or not he could come onto the show full-time. Unfortunately, actor Russell Tovey is still tied up on ABC's Quantico, so he's not available in the near future. However, Guggenheim said that there was a plan in place.

"We do have a plan for how to replace Firestorm on the bridge, and it's a really cool one. It's one we're really excited about." Guggenheim continued, "There's really like two empty chairs on the Waverider. So we do have a game plan. We've always had a game plan. I just can't talk about the game plan. The CW publicity will determine when we get to unleash that bit of news."

Since he couldn't reveal exactly who was coming to Legends, we asked if Guggenheim could at least tell us if the character was already in the Arrowverse or if they would be new to the party.

"It's a returning," Guggenheim hesitated. "It's a previously established character from the Arrowverse."

We already know the Ray is out of the question but that isn't saying much, considering the Arrowverse is full of characters that could find a home with the Legends.

One strong possibility fans are hoping for is Matt Ryan's Constantine. The beloved character, who's own show was cancelled on NBC after one season, is set for a guest arc on Legends when the show returns in the Spring.

Perhaps Firestorm's absence could lead to a permanent position for Constantine on the Waverider. Another popular option amongst fans would be Kid Flash himself, Wally West (Keiynan Lonsdale).