Dragon Slayer II: Xanadu (ザナドゥ Zanadu) is an early action RPG developed by Nihon Falcom and designed by Yoshio Kiya. It was released in 1985 for the X1, PC-88, PC-98, FM-7 and MSX computers. Enhanced remakes were released for the Sega Saturn, PC-98 and Windows systems. It is the second in the Dragon Slayer series, preceded by Dragon Slayer and followed by Romancia, though they, as most games in the Dragon Slayer series, have very little relation to each other beyond some key gameplay concepts.
Xanadu is notable for several reasons, including its sales record for computer games with more than 400,000 copies sold in Japan, in 1985, making it one of the best-selling computer games of the 1980's. In Japan, it still remains one of the best-selling computer games through to the present day, along with Thexder. With ports and re-releases, it is estimated to have sold at least 1 million units in total.
Xanadu was one of the foundations of the RPG genre, particularly the action RPG sub-genre, featuring real-time action combat combined with full-fledged RPG elements such as character statistics, innovative gameplay systems like the Karma meter and individual experience for equipped items, and platformer elements combined with the dungeon crawl gameplay of its predecessor. It also had towns to explore and introduced equipment that change the player character's visible appearance, food that is consumed slowly over time and essential for keeping the player character alive, and magic (in the form of projectiles) used to attack enemies from a distance. In dark areas, the player also needs to light up a lamp.
The game's side-scrolling perspective and open-ended gameplay also laid the foundations for the Metroidvania-style of action-adventure gameplay. The game's use of separate battle screens for real-time combat (often transitioning from a side-scrolling to top-down perspective for combat) was also a precursor to the gameplay style of later action RPG's such as the Tales and Star Ocean series. In addition, the way Xanadu changed the story and gameplay from its predecessor influenced the Final Fantasy series to do the same with each of its sequels.
The following year, 1986, saw the release of Xanadu Scenario II, an early example of an expansion pack.