Where did Fionna and Cake come in? They’re gender-swapped versions of Finn and Jake who first appear in fan fiction written by “Adventure Time” villain the Ice King. The duo were created by character designer Natasha Allegri, and appeared in a series of web comics and drawings before being given “Adventure Time” segments of their own. In the new show, Fionna lives with her cat, Cake, working dead-end jobs in a world without magic until the pair is flung through the multiverse, pursued by a powerful foe.

The Washington Post recently spoke with showrunner Adam Muto and supervising director Ryann Shannon about the spinoff. This interview has been edited for length and clarity.

Q: In the original series, there were episodes about Fionna and Cake. What about those characters made you interested enough to do a spinoff series about them?

Muto: A lot of it came from just the voice actors and how they really inhabited the roles in just a few episodes. So it already felt like it could potentially be a thing pretty early on, not that it was actively pursued by the network, but some people, [the] only episodes that they like are the Fionna and Cake ones, and it’s very strange to think of it in those terms. But I think that’s kind of the beauty of “Adventure Time” — people came to the show for different things and they really like those things.

Q: What about Finn and Jake’s story made you want to explore it through this gender-bent lens?

Muto: That came out of just playing with fanfiction [gender-reversal] tropes. One of the character designers at the time, Natasha Allegri, originally came up with the drawings based on that. I think she was just doing it for fun. … It was difficult because they are so closely linked to Jake and Finn, and when we did those episodes, it was like, “Why isn’t this just a Finn and Jake episode? What can we do differently?” So the series is kind of an extension of that question: How can we differentiate them?

Q: How did you define Fionna and Cake as individual characters while still allowing them to be alternate versions of Finn and Jake?

Shannon: Fionna and Cake are just their own characters. Fionna is going through, at least in this series, real-world issues at first and just kind of experiencing life as a normal girl in her early thirties who wants more from life. And Cake, at the beginning, is just a cat. It’s exploring the dynamic of two characters that want more from life. I think that’s just very different from Finn and Jake, who are already in their world and doing their thing.

Muto: Yeah. Finn was sort of originally a bombastic character, and it was pushing that as far as it could in a lot of episodes, especially early on, where he just wanted to help people so bad it tore him apart. And Jake was sort of supremely powerful, but also really lazy, so he wouldn’t really exercise those powers. Cake we tried to make a little more feral and more catlike. She’s not quite as completely loyal as Jake. She’s independent and has her own things that she wants.

Q: How did you balance reimagining the story with wanting to bring in familiar faces?

Muto: I think a lot of that was just in the writer’s room and in the boarding, how much an episode could hold. It became clear when you were trying to fit in one too many things or it was diffusing the attention too much. So a lot of the characters that ended up showing up were the ones that had analogues in the other [“Adventure Time”] episodes, so that we could get that contrast, as opposed to just trying to cram in as many as we possibly could.

Shannon: I don’t think it’s like cameo-fest, but it is a thing where you’ll see a character in the background and you’ll be like, “There they are.” Which I feel like, does that job. If you like a character, you’ll like it even if you just see them for a couple frames.

Q: There have been a lot of sequels and reboots released recently, with mixed success. Was there ever any concern about adding to these stories?

Muto: Absolutely. We had the original series and we try not to touch it too much. There are appearances by characters from it, but I think I’m very conscious of like not stepping on what we’ve done before. … It’s a very weird dance now because so many of the things that get traction are [intellectual property]-based or legacy, and you want to make cartoons, but you also want new ideas to live.

Shannon: You just want to make sure that it’s satisfying on its own, as opposed to relying on predecessor stuff … Having the focus be on these characters and their growth helps me distinguish the projects.

Q: The original series got a lot of praise for its three-dimensional female characters and LGBTQ+ inclusion. Were these things that you were actively talking about, or did they happen organically as you were building out the characters and building out storylines?

Muto: On the original, we can’t take credit for that. I think a lot of it came out of the writers and artists who were involved and just them wanting their identities to be expressed and portrayed. You can see that taken to more overt lengths on “Steven Universe” and shows that followed.

Shannon: I think it’s nice everybody can put their identity into the thing that they’re working on, and I feel like “Adventure Time” is really open about that.

Q: With some streaming platforms opting to remove original content, are you concerned about the possibility of having your work completely erased from the only platform on which it appears?

Muto: Yeah, it’s gotten a little bit more intense. Shows used to get canceled and maybe two episodes would air and then the rest will be buried. That wasn’t so strange, but now it feels like the norms have become any show is up for grabs and might disappear and it might never come back. That is kind of horrifying, but it’s also freeing because we have no control over that. There’s nothing we can do and no way we can game performance to make sure we’re not the ones who get caught by that ax. It is very alarming from a cultural standpoint because you used to be able to work on a thing and even if it was poorly received or you didn’t necessarily love it, it existed — it was in the world and it could be discovered years later.

Q: Have you guys thought about doing more spinoffs?

Muto: Definitely, you know, even leading into this we pitched so many ideas because there was a period of real volatility at CNS [Cartoon Network Studios] and Warner Bros. and Warner Bros. Discovery in general. So we pitched so many different ideas and were just hoping to get some kind of green light. There’s grist for a lot, whether all those get made feels like it depends on what the appetite is and who’s willing to bankroll it, because you don’t have guaranteed buyers anymore.

Q: Is there anything else that you want audiences to know about the series?

Muto: It’s a weird show. I forget sometimes that the barrier is a bit higher, especially now with ten seasons of continuity. … This is definitely trying to show appreciation for the original series and people who watch the series and reward that without that pandering. So hopefully it’s enjoyable, but if you didn’t like it, you can write your own ending and that is equally valid.