Ys is a series of action RPGs developed by Nihon Falcom that follows the adventures of the red haired swordman, Adol Christin. The franchise began on PC-88 in 1987 and now consists of eight main titles, multiple ports, spin-off titles and remakes. The name Ys (pronounced "eece") is derived from western European legend, Ys being a mythical city on the coast of Brittany. Many locations in the world of Ys have counterparts in the real world.
- The series is known for its soundtracks, composed by Yuzo Koshiro ( Ys I and Ys II), Mieko Ishikawa ( Ys I, Ys II, Ys III, Ys IV, Ys V, Ys Origin), and Hideya Nagata ( Ys II), as well as their Sound Team J.D.K.
- Although Adol shipwrecking on the shores of a new continent is a running joke among Ys fans, Adol rarely actually shipwrecks at the beginning of any of his adventures. The first Ys title was the only entry in the series to contain a shipwreck for many years until the release of Ys VIII in 2016, all other mainline Ys games saw no harm come to the ships Adol boarded.
- There are technically four versions of Ys IV that were all created by different companies, only one of which was Falcom themselves. The first to be published were Mask of the Sun by Tonkin House on the Super Famicom and Dawn of Ys by Hudson on the PC Engine-CD, which were released within a month of each other in 1993. Both versions followed the same basic outline that was created by Falcom but featured totally different structures and interpretations of the story, but Mask of the Sun was considered to be the canonical fourth entry. Years later Taito developed a remake of Mask of the Sun in 2005 for the PlayStation 2 called Mask of the Sun - A New Theory and finally Falcom released their own re-imaging of Ys IV for the Playstation Vita called Ys: Memories of Celceta in 2012.
- All the numbered Ys games are suppose to be stories from Adol's collection of personal travelogues that he wrote during his many adventures. The journals are being narrated by some kind of historian, implying that the red haired adventurer has already passed on. The games even explain that the reason Adol is silent is because he would write his journals as if the reader was experiencing his adventure instead of himself.