Rooster Fighter

Three years ago, mutant demons began appearing in Japan. While some are harmless or helpful towards humans, others are troublesome. Created from humans suffering from extreme emotional distress or unresolved trauma, these mutant demons began to wreak havoc as they began to evolve to be more intelligent and dangerous. A lone rooster named Keiji wanders around various cities of Japan while defeating mutant demons he encounters. His ultimate goal is to find and kill the mutant dubbed "The White Demon" who killed his sister, Sara, to avenge her death.

Keiji (ケイジ) Voiced by: Kenta Miyake (Japanese); Patrick Seitz (English) A self-described "migratory bird" who vows to defeat the demon that killed his sister. He wanders around Japan and has a policy to never stay longer than necessary. Keiji has a strict code of conduct that he follows regarding respect and appreciation. Despite despising children or any youngsters that he deemed disrespectful or annoying, he has a soft spot for some of them, like Piyoko. His abilities include a powerful Cock-a-doodle-doo that induces resonance and great aim when throwing items with his beak. Elizabeth (エリザベス, Erizabesu) Voiced by: Mariko Honda (Japanese); Luci Christian (English) Adopted into a wealthy family shortly after her birth, Elizabeth is a hen who lived a luxurious yet dissatisfying life when she witnessed a demon wreak havoc on her city and nearly kill her and her family. It was Keiji who rescued them, and she immediately fell in love with him, only to be abandoned right after their short affair. She ended up resenting Keiji for abandoning her and initially trained herself to get revenge against him; however, as she witnessed more mutant demons kill off her loved ones after Keiji's departure, she began training to defeat them for the next six months. After reuniting with Keiji, she decides to join his efforts in fighting against the White Demon. Elizabeth fights with a lightning staff and is shown to be tech-savvy. Piyoko (ピヨコ) Voiced by: Shiori Izawa (Japanese); Kimoy Lee (English) Raised by a yakuza to initially be sold with other chicks, Piyoko became a beloved pet instead before witnessing her owner turn into a mutant demon. Witnessing Keiji defeat and save her owner, she decides to follow him on his journey to defeat the White Demon, and Keiji reluctantly lets her join him after she helped nurse him back to health. She is attached to him, believing that she will marry him once she is older, and was given the name Piyoko by him after asking for a name. She has the word "Duty" (仁義, Jingi) written on her back after asking her former owner to give her a tattoo similar to his. For reasons unknown, Piyoko does not age, as she remains in her chick form after travelling with Keiji and Elizabeth for months. Morio (モリオ) Voiced by: Mitsuaki Kanuka (Japanese); Roger Rose (English) A friendly demon who was manifested by a middle-aged man who was diagnosed with terminal stomach cancer, but was abandoned when his human host learned of his misdiagnosis. After constantly being attacked by locals, Morio shrank to human size and has lived his life as a hermit when he meets and befriends Keiji. Keisuke (ケイスケ) Voiced by: Tomohiro Ōno (Japanese); Robbie Daymond (English) Keiji's younger, crested half-brother who matches him in strength. He joins Keiji on his quest in order to rescue their father after he is captured by demons.

One-Eyed Silver (片目の銀, Katame no Gin) A one-eyed sea turtle with a personal vendetta against birds after witnessing a flock of gulls eat his siblings after hatching; he is initially hostile towards Keiji. However, he helps him defeat a demon at sea after realizing that Keiji was not like the seagulls he despised. He lets Keiji off to go avenge his sister but makes him promise that they will have a proper battle once he returns. Zena (ゼナ) An elderly toucan taken from his home in Brazil and now overseeing the Southern Birds exhibit in the zoo, he took Keiji into the exhibit after finding him unconscious in the rain. He was a beloved member of the community and protected his bird family from a demon attack before succumbing to his injuries. Keiji took one of his feathers, hoping to return it to Zena's sisters one day. Sara (サラ) Voiced by: Hikaru Tono (Japanese); Erin Yvette (English) Sara is the sister of Keiji. It is Sara's death that led Keiji to avenge her; however, Keiji noted that the bird used by the White Demon resembles her. Gakuma (嶽磨) / White Demon (白鬼獣, Hakkijū) A white-skinned and four-horned demon. The mutant is responsible for killing Keiji's sister, Sara. Known as the "White Demon", he is a giant that also has a fire-like bird that it uses to burn what it wants. He also has a circular mark on its neck, which Keiji uses to identify it. He is later revealed to be the leader of all demons, and to have the human form of a young man named Gakuma. Kugone (クゴネ) Voiced by: Yūko Kaida (Japanese); Anjali Kunapaneni (English) Gakuma's right-hand woman who is creating demons all over Japan on his orders. Yuji (裕二, Yūji) Voiced by: Jun Kasama (Japanese); Alejandro Saab (English) Hikari (ヒカリ) Voiced by: Natsumi Fujiwara (Japanese); Zeno Robinson (English) Keizan (ケイザン) Voiced by: Akio Otsuka (Japanese); Kirk Thornton (English) Keiji, Keisuke and Sara's father.

Written and illustrated by Shū Sakuratani, Rooster Fighter started on Hero's Inc.'s Comiplex manga website on December 18, 2020. The series' first tankōbon volume was released on May 1, 2021. As of April 3, 2026, twelve volumes have been released. The manga is licensed in North America by Viz Media, with the first volume released on August 16, 2022.

In July 2024 at San Diego Comic-Con, it was announced that the manga would receive an anime television series adaptation in collaboration with Hero's Inc. The series was produced and licensed outside of Asia by Viz Media under the collaborative label Viz Media Hero's, while Sanzigen handled the animation. Sola Entertainment contributed as an associate producer (with the company's CEO, Joseph Chou, serving as its representative). It was directed by Daisuke Suzuki, with Hiroshi Seko handling series composition and music composed by Tetsuya Takahashi. The 12-episode series premiered English dubbed in the United States on Adult Swim's Toonami programming block from March 15 to May 31, 2026, before streaming the same day on Hulu (in the United States) and Disney+ (internationally) shortly after each linear broadcast. The streaming release includes the Japanese subtitled version. It also premiered in Japan on Tokyo MX, Cartoon Network Japan and BS NTV approximately three weeks later from April 6 to June 22, 2026. The opening theme song is "What's a Hero?", performed by Daruma Rollin', while the ending theme song is "We're Loose Stars", performed by Tetsuya Takahashi. Medialink licensed the series in the Asia-Pacific for streaming on Ani-One Asia's YouTube channel and Crunchyroll.