At San Diego Comic-Con, I interviewed Iowa-native, author, and illustrator Wendy Martin, creator of the lighthearted fantasy series Castle Swimmer. Readers may recognize the title as part of the WEBTOON Originals catalog. As a webcomic, Castle Swimmer launched digitally as an Original in January 2019 and has been a long-time fan favorite because of its found family elements, compelling themes on free will and responsibility, and healthy queer representation. However, as of October 2024, Ten Speed Graphic released the first physical volume of Castle Swimmer, containing episodes 1-19, and a never-before-seen bonus chapter featuring Kappa and Siren. Later in June 2025, Ten Speed Graphic released the second volume of Castle Swimmer, containing episodes 20-41, as well as an additional bonus chapter. The third volume was announced for release in March 2026, much to the excitement of existing fans.
For those who are unfamiliar with this series, Castle Swimmer, the highly popular and beloved Boys Love webcomic, follows the story of two merfolk named Kappa and Siren whose lives are intertwined by destiny and expectation. From the moment he was born, Kappa’s life purpose was decided. He was the Beacon, destined to fulfill many prophecies and serve as a light to all sea creatures. Leading a life led by self-sacrifice, Kappa finds himself next in the Shark Kingdom, where he is immediately imprisoned. Among the Sharks, it is prophesied that their communal curse will be lifted once their prince, Siren, kills the Beacon. But Prince Siren has no desire to kill Kappa, especially after getting to know him. Instead of fulfilling his destiny, Siren helps Kappa escape, leading to an underwater adventure that brings them closer together.
In this SDCC exclusive interview, Wendy Martin details her inspiration for Castle Swimmer, her chaotic creative process, and her lifelong interest in comics. Martin also shares about her transition from digital to traditional publishing and provides hints regarding her next project, in which readers can look forward to a world where the sky is the limit. If YOU want to learn more about Martin, how Castle Swimmer came to life, and what the future could hold for her, keep reading.
Wendy, what can you tell us about yourself and your creative projects?
I’m kind of a one-trick pony. After Castle Swimmer, we’re moving on to my next project. Instead of in the ocean with fish boys, we’ll be in the sky with bird boys, so almost the same thing, just in a different location with a different theme. I’m really excited for it, but I have to keep telling myself that you’re not allowed to think about the bird boys until you finish Castle Swimmer. You gotta focus on one. But I’m very, very excited for both.
What led you to become a comic creator?
I actually always wanted to make comics ever since I was little. My interest in comics started with those short newspaper comics, and then when I got into high school, I got into manga. I transitioned into a different comic format, and then from there, closer to college, I got into webcomics. So, I’ve always been obsessed with comics, just like different versions of them.
How would you describe your creative process as a comic creator?
Chaotic. I would not recommend my process to others, but I feel like my whole life revolves around making comics, and I kind of like it that way, just because I’m obsessed with making comics. So, just like everything at all times, I’m thinking about making comics in the shower, I’m thinking about comics and all, where I eat when I do. This is all adapted to my schedule, making comics.
Who or what would you say inspired your storytelling style?
Weirdly enough, most of my inspiration for writing stories came from, like, video games and video game stories. Like, a big influence was, like, Shadow of the Colossus. I’m not sure how that relates to Castle Swimmer, but that was, like, a deep inspiration. And I think it’s like the structure of video game storytelling and traveling. For some reason, that really resonates with me and inspires my comics. A lot of video games, and then various comics that I grew up reading as well, helped to inspire the stories that I write.
What would you suggest to any aspiring comic creators looking to publish or even just start?
I think just starting is like the hardest thing. Because you can get trapped in that, that era of preparing for your story endlessly, and not feeling that you’re good enough to start your magnum opus. You don’t have to start with your magnum opus. Just start making comics, whatever medium you want. It’s actually the quickest way to improve and grow.
With webcomics becoming more popular, driving many to be adapted into graphic novels, live-action films, and even animated television series, did you ever desire Castle Swimmer to be in print?
Yes, I did desire that. Honestly, there was a point when I started turning it into a webcomic. Because when I first started Castle Swimmer, it was actually in traditional format, ready to be turned into a book, but when it got picked up for WEBTOON, I was like I guess it’s online forever, and it’ll never be a book, so I committed to the scrolling format. The fact that I later got the opportunity to turn it into a physical book was a dream come true.
With two volumes of Castle Swimmer published and the third volume set for March 2026, how do you feel about being able to hold physical copies of your series?
It is crazy. It’s amazing. When I was a kid, the only nice bookstore we had was Barnes & Noble, so I would always go there and look at all the comic books. And now my book is there, which is crazy. So, yeah, it’s a dream come true.
What originally led you to use WEBTOON as a storytelling platform to publish your comics and reach an online audience?
Honestly, WEBTOON was the last place I posted my comic. Before WEBTOON, I posted it everywhere. I didn’t know about WEBTOON at first, because I was coming off the webcomic scene, where people make their websites and various places to post their comics, and it’s all connected. I had a little WordPress website I made, and then WEBTOON was rising in popularity at the time when I started working on Castle Swimmer, and I was posting on a platform called Tapas. And I was like, You know what? I’ll just slap it on WEBTOON. I’m not gonna reformat it. I’m just gonna stick it on there and see what happens. I was still waitressing at the time, and then I got an email from WEBTOON that was like, Would you like to get paid to make this story full-time? I’m like, Yes, yes, please.
How did or has working with publishers WEBTOON and Ten Speed Graphic affect you as a creator?
It’s interesting because one is like a strictly digital way of working, and one is like the traditional space. It’s interesting to see how they work. I feel like with WEBTOON, everything moves at such a fast pace because it’s very tied to social media. So you’re always like, chugging along, going as fast as possible, whereas when you’re working with traditional books, there’s kind of more of a slow process. There’s a lot of like, back and forth, double-checking, and collaboration. So they are super different, which surprised me, but it’s kind of nice to experience both.
What would you argue was the main inspiration for Castle Swimmer, and what drove you to tell this particular love story that has won so many hearts?
The main thing that inspired Castle Swimmer was the Kingdom Hearts game, and it was the Little Mermaid section. For some reason, Sora with the swords really sparked this idea of mermaids with swords, having an adventure underwater. That sounds like such a cool thing. So that was the initial spark for the story, and it just kind of evolved from there. And I love queer romance. Of course, it was gonna have a queer romance, no matter what story or world it was.
With Castle Swimmer launched in January 2019 as a WEBTOON Original, how would you argue that this series and its characters have evolved over the past six years?
They have changed a lot because of the horrors that I put them through, for sure. But I always write their dialogue, kind of from a personal space, and since it’s been so long, I started Castle Swimmer in my 20s, and I’ve changed as a person a lot, and I feel like that is often reflected in the dialogue of my characters and how they react to things. So I feel like as I’ve grown, they have grown as well, and they sound more mature when I write them now as opposed to when I started. So it’s like they’re little mini versions of me, in a way.
Who is your favorite Castle Swimmer character, and why? Has your favorite child changed over the years?
I love all my children equally, of course, but I do have, like, favoritism that comes out sometimes. In Season One, there was a character who was originally going to die, and his name was Skiff, and I just really liked him, so he lived. And certain designs that are fun to draw, I tend to like more. I like my mascot character a lot. He’s very fun to draw, of course. Then, a later character named Galoo. She’s based on a little sea bunny. I just love her so much. I love her so much. Don’t worry, readers, she’s safe. Nothing will ever happen to her, because I love her so much.
Is there anything you would like to say to your fans who couldn’t attend Comic-Con this year?
I just want to thank them for all their support because they’re the main reason this series exists. It is from their support over the years. So, thank you. I will forever be making comics because of your support, and I will always provide cute little queer love stories and fantasy worlds.
In July 2025, Castle Swimmer returned for its fourth and final season on WEBTOON. Stay tuned and tell us in the comments if this interview with author Wendy Martin convinced you to read Castle Swimmer and explore the seas with Kappa and Siren.
