is a series of hack-and-slash action video games created by Sega. The ninja (shinobi) Joe Musashi is the protagonist of the original series of games (Shinobi to Shinobi III). The first Shinobi game was released in 1987 for arcades. Along with Alex Kidd and Sonic the Hedgehog, Joe Musashi has long been one of Sega's flagship characters, acting as a mascot for a short time in the late 1980s when ninjas were popular in mainstream media. The series' games are a showcase of Sega's technical accomplishment, noted for their high quality of graphics, gameplay and music, as well as their high level of difficulty. The Shinobi franchise sold more than 4.60 million copies. The main character of Shinobi (the original Japanese word for "ninja") is most commonly associated with that of Joe Musashi, the protagonist of the original arcade game and many of its sequels. His name is a combination of both an archetypical Western first name and Japanese last name, Musashi likely being derived from the legendary Japanese swordsman Miyamoto Musashi. In the manual of The Revenge of Shinobi, Musashi's backstory is told as that of a weak boy who first entered the dojo of the Oboro clan at a young age and gradually, through tireless practice and meditation, worked himself up to become the most skilled and respected ninja of his clan. His peaceful existence in the mountains of Japan is shattered when the ninja crime syndicate Zeed rises to power and attempts to revert Japan into the Sengoku period of civil war when the ninja thrived. After being defeated by Musashi in the original Shinobi, Zeed reforms three years later as Neo Zeed and attacks the Oboro clan directly. With his master assassinated and his girlfriend Naoko kidnapped by the enemy, Musashi swears revenge, and in the ensuing battles through a series of locations in Japan and America, as chronicled in The Revenge of Shinobi, all but annihilates Neo Zeed. When Neo Zeed returns in Shinobi III: Return of the Ninja Master, Musashi comes out of retirement one last time and destroys them for good.