Ninja Gaiden Shadow, released in Japan as Ninja Ryūkenden GB: Matenrō Kessen (Japanese: 忍者龍剣伝GB 摩天楼決戦, literally “Legend of the Ninja Dragon Sword GB: Skyscraper Showdown”), and in Europe and Australia as Shadow Warriors, is a side-scrolling action game released for the Game Boy in 1991 by Tecmo. It is a spinoff of the Ninja Gaiden series.