'Agents of SHIELD' Season 5 Finale Could Serve as a Series Finale

Is this the final season for Marvel's Agents of SHIELD? If that ends up being the case, the series' showrunners say they're ready.

That's not to say that they're not hoping for a season six renewal, but Jed Whedon and Maurisa Tancharoen tell TVLine that they're writing the season five finale with the thought that it may actually be the show's series finale very much in mind.

"We are in process [of writing the finale]," Whedon said on Saturday the show's Episode 100 celebration.

Tancharoen added, "We know what it is."

That is, they know what the finale's story will be, and it could be used to end the season or the show entirely.

"Yeah, we're ready for if this is the end," Whedon said. "We're definitely going to make it rewarding either way.

"We can certainly pivot and there are certain things that we're putting in that at the last minute could be adjusted," Whedon continued. "But we know at the end we're not moving off that mark. We're going to do what we were planning to do, and I think that it'll be thrilling either way."

Marvel's Agents of SHIELD is currently in a tough position. It holds a late Friday night time slot and its average 2.3 million viewers the smallest audience of any ABC drama. It's average 0.6 rating in the key demographic is the network's second lowest next to Once Upon a Time, which is in its final season.

However, Marvel's Agents of SHIELD sees a 117 percent demographic bump when Live+7 DVR numbers are taken into account, which is the fourth-largest increase in all of network television. It's unclear how much ABC values the delayed viewing numbers, but ABC head Channing Dungey said at the TCA press tour that she is "cautiously optimistic" about SHIELD's chances at a sixth season.

"The creative this season, I honestly think, has been the strongest its ever been," Dungey said. "We've been really excited about what the producers have been talking about for the second half of the season. I'm really looking forward to hearing them come in and talk about what their ideas would be for season 6, so we can make a better determination about whether we're going to order another season or not."

Marvel's Agents of SHIELD airs Fridays at 10 p.m. ET on ABC.