The Hundred, a group of scholars and philosophers devoted to peace in ancient times, fled the growing corruption of the Roman Empire. Traveling to the moon using alchemical means of their own devising, they built a lunar shrine and waited for humanity to be ready for their message of wisdom and understanding. They decided to bless a man on Earth with great powers and longevity to carry their message around the world and selected a young poet named Anteides. They beamed a portion of their alchemical power into a clearing where he prayed nightly. The beam struck Valkus, a jealous rival of Anteides and member of Emperor Claudius' Praetorian guard, who had just murdered Anteides. Cruel but charismatic, Valkus used his new found abilities and longevity to become the Centurian, waging war across the years, seeking to become the ruler of the world.
Powers and Abilities
Extremely long lived, Centurian's other abilities are listed as "Hypnotic influence, uncanny perception, and his Ghost Army." He is shown to exert some influence over Moon Maiden when they return from being trapped outside normal space-time, turning her against her former allies in the JLA. He also manifests a army made up of the reanimated souls of everyone who has died serving under him in over two-thousand years of warfare. While he is shown in hand to hand combat with Wonder Woman, it is not clear if he has any physical abilities beyond a normal human being.
In addition to his alchemical powers, Centurian has access to advanced technology, most notably a gun that erases its targets from history, completely cutting them free from causality, and eventually from the world's memory. At one point he uses this on Alan Scott, and while the effect is not immediate, a few days later his children Jade and Obsidian disappear from reality. This effect is apparently not permanent, as Centurian himself was caught in an explosion of the device, and both he and Moon Maiden (who was also caught in the blast) were removed from reality, only to return five years later.