Adorable fire salamander Bruni was one of the most popular new characters introduced in Frozen 2, so fans may have been disappointed that he doesn't get much screen time. In fact, Disney and the Frozen 2 production team did realize just how much audiences would love Bruni, but not until it was too late to give him a substantially bigger role.
Behind-the-scenes documentary Into The Unknown: The Making of Frozen 2 was recently released on Disney+, and offers an interesting look at the huge amount of work that went into every frame of the highly-anticipated sequel. It also reveals just how much pressure directors Chris Buck and Jennifer Lee were under to deliver a worthy follow-up to one of Disney's biggest movies of all time. No more is that pressure felt than when the production team head to a theater in San Diego, where a rough cut of Frozen 2 is screened for a test audience for the first time .
During the audience preview, the response cards had a list of characters so that attendees could select their favorites - but Bruni wasn't even on the list. The production team realized how big a hit the character was when many audience members wrote him in as their favorite. After receiving the feedback, Lee went into extensive rewrites, primarily to make the movie's plot less confusing for kids and to add more comedy in, but also to add Bruni into some more scenes.
Though Bruni may have ended up with a bigger role than he originally had in the script for Frozen 2, the audience preview took place just five months before the movie's release, and even short scenes take a long time to animate. Overall, Frozen 2 took roughly four years to make, so the final five months were more for story tweaks and fine-tuning. In the theatrical cut of the film, Elsa discovers Bruni in the Enchanted Forest and realizes that he is responsible for the magical fires that have been springing up. This scene was always in the movie, but Bruni's occasional appearances throughout the rest of Frozen 2 appear to have been added in response to the test screenings.
There's been no formal word yet about Frozen 3 being in the works, and Disney will likely want to take its time and make sure the right story idea is in place before moving forward with a sequel - if it happens at all. If Frozen 3 does go into development, however, it's a pretty safe bet that Bruni will return, and fans will get to see a lot more of the cute little fire salamander.