The first game, Demon's Souls, was released exclusively on the PlayStation 3 in Japan on February 5th 2009. It was never planned to be released outside of Japan, but due to its positive reception and being import-friendly, it quickly gained popularity among a niche of players in the West. This led to it being published in the North American and PAL regions in October 2009 and June 2010, respectively.
Dark Souls, which is not a direct sequel but rather a spiritual successor, was released in October 2011 on both PS3 and Xbox 360, with a PC release following a year later in response to a fan petition. One DLC pack (the first DLC for this franchise) was released for the game at the time of the PC release. Dark Souls put the Souls franchise on the map for the broader gaming community, as its multiplatform release gave many new players their first chance to play a Souls game.
In 2014, Dark Souls II was released on PS3, Xbox 360, and PC. The game featured more content across the board than either previous Souls game, including more levels, bosses, weapons, and spells. Three DLCs packs were released throughout 2014.
Dark Souls II: Scholar of the First Sin is a re-release of Dark Souls II that was released in 2015 in two varieties: an 'old-gen' version for PS3, Xbox 360, and PC (DirectX 9), which packages in all of the DLC and includes some small game enhancements, and a 'new-gen' version for PS4, Xbox One, and PC (DirectX 11), which includes everything that the old-gen version does as well as a more technically advanced game engine and new enemy placement throughout the game.
In his Giant Bomb interview, creator Hidetaka Miyazaki mentioned the influence of several classic manga on his game designs for the Souls series, including Saint Seiya, JoJo's Bizarre Adventure, and Berserk.
Among video games, Miyazaki cited the influence of the early Dragon Quest games, and particularly the influence of Ico, on the Souls series. The series was also influenced by FromSoftware's own King's Field series.
The Souls series have had a strong influence on a number of action RPG titles and the video game industry in general. Developers of games such as The Witcher 2, Destiny and Alienation have cited the Souls games as influences. The innovative asynchronous online multiplayer of the Souls series also influenced games such as Journey and the development of the PlayStation 4.
Some games have cited Dark Souls as a specific holistic inspiration, such as Lords of the Fallen and Salt and Sanctuary.