‘ChaO’ Envisions a Futuristic Mermaid World You’d Want to Visit

IndieWire spoke to director Yasuhiro Aoki and character designer Hirokazu Kojima about creating the completely unique world of "ChaO," a futuristic paradise where mermaids and humans live in uneasy coexistence.

Cinematic history is littered with stories of man falling in love with mermaids, from “Splash” to Disney’s retelling of “The Little Mermaid.” But none looked quite like “ChaO,” a new anime film released in the U.S. by GKIDS this April.

Set in a vague but beautifully futuristic world (referred to as “20XX” in a title card) where robots exist and mermaids are a known species in a tenuous peace with humankind, “ChaO” follows Stephen, a lowly employee at a shipbuilding company with big dreams nobody takes seriously. When the titular Chao, the daughter of mermaid king Neptunus, suddenly appears in his life proposing marriage to him, the hapless Stephen agrees less out of attraction to the spirited, sweet princess — who has a gorgeous humanoid form underwater but looks like a big plump goldfish on land — and more because the marriage’s publicity elevates him to a position of stature that leads to the greenlight of his big supership idea. Still, Chao is besotted with him, and navigating their odd arranged union leads Stephen slowly to learn how to care for someone so different from him.

“ChaO” is the directorial feature debut of Yasuhiro Aoki, who has worked at animation company Studio4°C for two decades. Prior to making “ChaO,” Aoki served as a key animator for several projects that he said prioritized very realistic, grounded animation styles, such as 2024’s “The Lord of the Rings: The War of Rohirrim” and the “Psycho-Pass” film series. So for his directorial debut, he wanted to break away from that, resulting in the rubbery, exaggerated, fluid style that makes “ChaO” stick out.

“Maybe as a reaction, I wanted to go in a completely opposite direction,” Aoki told IndieWire in an interview. “But I know how to make it proper, so it’s really a mix of very exaggerated manga-like expression, as well as a little bit of realism.”

To create the world of “ChaO,” Aoki took inspiration from a short film he directed for the 2006 Studio4°C anthology “Amazing Nuts,” titled “Kung Fu Love,” which features a similarly impressionistic art style filled with loose-limbed characters. For the city Stephen and Chao live in, Aoki visited Shanghai during a location scouting trip, and was struck by how much more futuristic he found the city compared to those in Japan. From the sights he saw during the trip, he created the painterly backdrops that dot the film, which depict a twinkly metropolis that’s slightly different from our own while still warmly familiar.

Dotting the landscapes of “Chao” is an eccentric cast of characters that are often bizarre to look at — and not just the mermaids. Ordinary humans like Stephen’s selfish boss are depicted as giant walking eggs, while others are proportioned like bobble heads. Character designer Hirokazu Kojima told IndieWire that Aoki had rough ideas for the character designs, which were partially inspired by the art style of “Dragon Ball Z” creator Akira Toriyama’s classic gag manga “Dr. Slump,” that Kojima used as a launching pad for the final designs.

“We wanted various kinds of people living in this movie’s world,” Kojima told IndieWire. “Because it’s about them coexisting alongside one another.”

For the two drastically different character designs of the title character, Kojima designed the land fish form of Chao as a direct representation of her gigantic personality: she’s a big, awkward, and waddling chunky creature. The more humanoid water form, with her pale skin and flowing water hair, was designed in part to be an “ideal” woman, with Stephen learning to love Chao outside of that form serving as a primary arc for him.

Although “The Little Mermaid” seems like the most obvious inspiration point for “ChaO,” Aoki insists he didn’t really have the fairy tale or the Disney version in mind when creating the film. His main point of reference was actually James Cameron’s “Titanic,” another romance film between star-crossed lovers set on the high seas. Aoki said the 1997 blockbuster directly inspired the film’s framing device, in which a journalist living in a world where mermaids and humans live more closely integrated lives tracks down Stephen to write a story on what happened to him and Chao after they disappeared years before.

Although “ChaO” is primarily a love story between its two main characters, Aoki dots the film’s landscape with lovable supporting characters whose paths intersect with the protagonists. The two pick up best friends, a robot inventor and a kung-fu practicing woman, who have their own romance on the sidelines. The journalist interviewing Stephen in the future has his own flirtations with his mermaid editor. Aoki said he wanted to make the world of the film, as fantastical as it is, feel real and grounded via these character arcs occuring in the background.

“What I really wanted to make sure about the characters in ‘Chao’ is that they have their own lives, even though they’re not on screen,” Aoki said. “Even if they go frame out. It’s not like Stefan is living this grand life and then the side characters are just there. Everyone has their own grand life, you know?”

“ChaO” is playing in theaters now.