Ninku (忍空, Ninkū) is a Japanese manga series written and illustrated by Kōji Kiriyama.

The story follows an odd-looking 12-year-old boy named Fūsuke, a powerful warrior from the Ninku school of martial arts, who command a style that mixes ninjutsu and kung fu.

Fūsuke, the former captain of the first division Ninku corps journeys across the land with his pet hiroyuki and the hot headed Rihoko to find his Mother who was taken from him at a very young age by the Imperial Army leader Kochin.

Along the journey, Fūsuke and the others are tasked with finding and controlling the mystical sky dragons in order to become stronger.

[7] The manga resumed publication as Ninku 2nd Stage on December 5, 1994,[8] and finished after 27 chapters on September 4, 1995.

[37][38] Media Blasters's Anime Works brand released Ninku: The Movie with an English dub on VHS in 1998.

[40][41] Ninku was adapted into a 55-episode anime television series, produced by Fuji TV, Yomiko Advertising and Studio Pierrot, and directed by Noriyuki Abe.

The first ending theme for episodes 1 to 28 is "Soredemo Ashita wa Yatte Kuru" (それでも明日はやってくる, lit.

[55] Characters from the series also appeared in another Weekly Shōnen Jump crossover smartphone game Jumputi Heroes, released for iOS and Android in 2018.

[58] John Oppliger of AnimeNation attributed the low popularity of the Ninku anime series to its lack of compelling narrative development and the sequential lengthy story arc structure that make other shōnen action series like Naruto, One Piece and Bleach popular.

He praised the characters and animation of the fight sequences, but considered them repetitive and he stated that the show does not encourage much viewer loyalty.