Critical Role's 8 co-founders say this is how they turned their 'Dungeons & Dragons' home game into an Amazon hit

• 'The Legend of Vox Machina' season 3's final batch of episodes dropped on Thursday.
• Critical Role's eight cofounders gave BI insight into how their hobby game became an Amazon show.
• CR cofounder and Emmy Award-winning director Sam Riegel says they aren't done with the "Vox Machina" story.

"The Legend of Vox Machina," a Critical Role animated series on Prime Video, aired the last set of episodes from its third season on Thursday at midnight.

What started as a game played by a group of voice actors looking for things to do in their downtime has morphed into a mega nerdworld business. Critical Role, the company by the same name, has its own streaming platform, an independent game publishing arm, and investments in the audio drama business.

The founders, meanwhile, are now big names in geek country — in the US and beyond. They're working on two Amazon-backed series — a deal they secured with Prime Video after a $11.3 million Kickstarter fundraising round to create their show.

Business Insider sat down with all eight cofounders, who discussed how their "D&D" campaign's hundreds of hours of streamed content was rewritten and converted into an animated series.

"The writers' room collaboration was all of us getting on a whiteboard what the most important moments were to each of us," chief creative officer Matthew Mercer told BI.

"The Legend of Vox Machina" has had three seasons of 12 episodes apiece so far. But it was based on a 115-episode-long "D&D" campaign, where each livestreamed episode clocked runtimes of three to four hours.

This third season, CR co-founders Liam O'Brien and Marisha Ray joined their colleagues — Sam Riegel and CEO Travis Willingham — in the writers' room, taking the lead in crafting one episode apiece.

Mercer said the CR team wanted the story to develop "in a way that feels true to the original campaign, but also leaving room for some fresh new things."

And the crew also made "some slight changes to keep everyone on their toes," Mercer added.

"It can be hard at times to decide what things don't make it in, but that doesn't mean they never will," Mercer said. "Some things, we hold on to for later. We get to play with time and the timeline a little bit."

The plot thickens

At the end of "Vox Machina's" third season, the star-crossed lovers Vax'ildan (voiced by O'Brien) and Keyleth (voiced by Ray) finally get together — seemingly for a happy ending — after two and a half seasons of slow burn.

But the show also covers a tragic plot point: The death and resurrection of Percival de Rolo, a gunslinger played by CR cofounder Taliesin Jaffe.

Jaffe told BI he had some fun with what was, essentially, planning his own funeral.

"I wanted pomp and circumstance," Jaffe said.

He added that the season allowed another side of Whitestone — a city he helped create at the crew's "D&D" campaign table — to be brought to life.

"Whitestone is my baby," Jaffe said. "I love seeing any moment spent in a new location in that city that has haunted my dreams for a decade plus."

"Vox Machina" also features original music, which Riegel — a songwriter and two-time Emmy Award-winning voice director — worked on.

One of the songs Riegel wrote was about the Ruby of the Sea — a famed courtesan from Critical Role's second long-running "D&D" campaign. Mercer recorded the song, and it later became an episode-ending track.

On the casting front, CR's co-founders have looped their kids into recording for the show. Most recently, Ronin Willingham — CEO Travis Willingham's six-year-old son — had a small voice-acting role.

"I think a few minutes into it, he decided he didn't want to do what we were asking him to do. He wanted to be a dragon instead," Willingham said.

More stories to tell

Riegel and his crew have big plans for the future. And on Wednesday, Prime Video announced that CR is getting a fourth season of "Vox Machina" — a massive vote of confidence from Amazon in the crew's ability to keep its nerdworld investment humming.

Riegel told BI ahead of the third season's launch that the crew still has more stories to tell.

"As always, we left the season ending on the smallest of cliffhangers," Riegel told BI. "There's evil forces still out there to deal with."

The end of the third "Vox Machina" season also portends ominous consequences for O'Brien's half-elf rogue Vax'ildan, who must now pay a heavy price for having helped bring his friend Percival back from the dead.

"If we are lucky enough to tell the entire story — that we hope to, knock on wood — I think he's just getting started," O'Brien said of his character.

CR also has its "Mighty Nein" animated series in the works with Prime Video.

An official release date hasn't been announced yet, but recording for the show is already underway. Jaffe told BI that viewers can expect a "darker story" for the "Mighty Nein," as opposed to "Vox Machina's" heroic, dragon-fighting romp.

"That the show has grown not just into an animated series, but we're still going 10 years later, and there's comics and novels — it's very surreal," Ray told BI.