Prequel of the game for PlayStation3 called "Shirokishi Monogatari". Developed by Level-5. This manga prequel is called "Shirokishi Monogatari: Episode 0 Dogma Senki" (White Knight Chronicles Episode 0: Dogma War Chronicle). This is a web-exclusive prequel manga.

Story:

The story takes place 10,000 years before the actual game's story, in an era embroiled by war and chaos. The manga tells the story of another White Knight who predates the White Knight hero character of the game.

(Source: ANN)