The production team for the upcoming Under Ninja anime series has revealed four additional characters joining its cast. The anime is scheduled to premiere sometime in October 2023.
The additional voice cast members joining the show include Chika Anzai as Kawado, Choo as Ono, Shuuichi Uchida as Eita, and Sora Tokui as Noguchi.

They join a main voice cast that features Taito Ban as Kuro Kumogakure, Tarusuke Shingaki as Kato, Tasuku Hatanaka as Miracle Hibi, Atsumi Tanezaki as Suzuki, and Daiki Yamashita as Shion Hachiya.
Satoshi Kuwabara (The Dawn of the Witch) is directing the anime, with Keiichirou Oochi (The Angel Next Door Spoils Me Rotten) as series screenwriter, Nobuteru Yuuki (Orange) as character designer, Satoshi Motoyama (Beast Tamer) as sound director, and Shouta Kowashi as music composer. Tezuka Productions is handling the animation production for the series.
Other staff members for the show include Natsumi Yamada (Adachi and Shimamura) as prop designer, Reina Iwasaki (The Dawn of the Witch) and Akio Ujiie (Girlfriend, Girlfriend) as chief animation directors, Masami Saitou (How Not to Summon a Demon Lord Omega) as art director, Yumi Aburaya (The Dawn of the Witch) as color designer, and Takeshi Shimura (Fuuto PI) as photography director.
The original manga series by Kengo Hanazawa was first serialized in Kodansha’s Young Magazine on July 23, 2018 under the YanMaga KC Special label. Ten tankoubon volumes have been released as of May 2023.

DENPA releases the manga in English and describes the synopsis as:
After World War II, Allied Command in Japan developed a new agency to help manage terrorism and violence within the Pacific region. The agency was staffed with ninja and they were initially tasked to handle domestic affairs. Eventually that program grew to its current form, managing 20,000 ninja across a range of domestic and international affairs. One of those ninja happens to be Kudo. The seventeen-year-old high school loser is now poised to be the next line of defense against a potential surge in foreign assassins invading Tokyo.