A seven-volume series from Tow Ubukata published by Fujimi Shobo, this was the inspiration for Capcom's obscure PS2 action game of the same name. The story follows the conflict between two former freinds, Sieg Warheit and Victor Delacroix. Sieg is the protagonist, while Victor is the antagonist, fueled by revenge for the death of his lover and blaming Sieg, Victor seeks to bring Sieg into a pure pandemonium as retribution, not only against Sieg, but the entire world. To achieve this goal, Victor seeks to steal the Three Sacred Glyphs to release the demon Azrail. Sieg pursues Victor to stop him, possessing the ability to summon the Legions of Chaos to assist him in battle. The game adaption has gained a bit of a cult following over time and I'm sure that plenty would be interested in seeing the origin of the story.