[1][2][3] Player characters are 'Centurions': 'potent individuals of action', born on the first day of the century, and endowed with extraordinary skills and abilities, much like Warren Ellis's conception of Century Babies in the Wildstorm comics universe.

It has been released under the OGL with a freely accessible System Reference Document.

Each character gains two aspects from their background, two from what they did in the Great War, and a further two from the stories that would make up an imaginary novel about their life before the game started.

[6]: 424 It was released to positive reviews, quickly reaching #1 on RPGnet's rankings.

[8] Co-author Fred Hicks claims that as of early 2009, Spirit of the Century had sold 3,313 copies in a mix of PDF and print.