A ninja (忍者) or shinobi (忍び) was a covert agent or mercenary in feudal Japan. The functions .. The mudrā, a series of hand symbols representing different Buddhas, was applied to the kuji by Buddhists, possibly through the esoteric Mikkyō. To help personalize their wardrobe and identify themselves, the ninja in the world of Naruto will often adopt certain markings. These can be clan symbols, tattoos. Free vector icon. Download thousands of free icons of signs in SVG, PSD, PNG, EPS format or as ICON FONT.