The Soul series is a series of weapon-based fighting games by Namco. It's also known as the SoulCalibur (or Soul Calibur) series since it only has one game that is not titled "SoulCalibur", the first episode titled Soul Edge or Soul Blade. Note that its name is not Soul, but Soul Series, as it's officially known in Japan.
The story revolves around a sword that, after years of bloodshed and hatred, gained a soul of its own, the Soul Edge, and the sword forged to counter it, Soul Calibur.
A total of 10 games have been released, including 6 main games and 4 minor titles. Many episodes also received upgraded re-releases, that included new characters or features (we count 6 of them, making a total of 16 releases, but this number is highly arguable).
Main games and revisions
Soul Edge (January 29, 1996), Arcade.
Soul Edge Ver. II (May 16, 1996), Arcade.
Soul Edge (December 20, 1996), PlayStation. Known outside Japan as Soul Blade.
SoulCalibur (July 30, 1998), Arcade.
SoulCalibur (August 5, 1999), DreamCast. Re-released for Xbox Live Arcade in 2008 and for iOS in Japan in 2012.
SoulCalibur II (July 30, 2002), Arcade.
SoulCalibur II (March 27, 2003), PlayStation 2, GameCube, Xbox. Each of the three versions features a different exclusive character and is therefore considered by some a different revision.
Soulcalibur II HD Online (November 20, 2013), PSN, XLA. Both versions include the exclusive characters from the PS2 and Xbox versions, but not the GC version.
SoulCalibur III (October 25, 2005), PlayStation 2.
SoulCalibur III: Arcade Edition (2006), Arcade.
SoulCalibur IV (July 29, 2008), PlayStation 3, Xbox 360. Each version features an exclusive character, later made unlockable for the other version.
SoulCalibur V (January 31, 2012), PlayStation 3, Xbox 360.
SoulCalibur Legends (November 20, 2007), Wii. An action-adventure game.
SoulCalibur: Broken Destiny (August 27, 2009), PSP. Basically a portable version of SoulCalibur IV.
Soulcalibur: Lost Swords (February 6, 2014), PSN. A free-to-play game based on Soul Calibur V. Service of the game terminated on November 30, 2015.
Soulcalibur: Unbreakable Soul (May 8, 2014), iOS.
A SoulCalibur manga was published in five volumes in 1999 to coincide with the release of the game.