Infidel is the eternal enemy and opposite number to Samaritan. Originally born as Kiyu around Kenya centuries ago even as a boy he craved for knowledge about the world. He travelled all the way to Zanzibar, where he was promptly reduced to slavery in Persia.
The rebellious boy was sold to an alchemist as a lab assistant, and learned innumerable secrets. Often insulted as an infidel, the contrarian Kiyu claimed this as his name. He continued to clandestinely study the alchemist’s material, and proved himself a genius. While still in his late teens, the Infidel used his knowledge to summon the very fire of space and time within his body, gaining energy manipulation powers. This infusion of energy also made his hair and eyes green. The Infidel established a compound in an isolated corner of the Middle East to resume his studies, but his taking of slaves and experimental subjects among the locals led to retributive raids he found insufferable.
The Infidel’s studies led to a better understanding of space-time energies and he learned to travel through time. He left for the post-apocalyptic XXXVth century, where he established his newest headquarters there. Though the few human survivors in this time period were soon to be extinct, the time traveller had a broader knowledge base than just science and could thrive even on a dead planet. The Infidel then travelled back in time to famous historical catastrophes, offering locals to save their lives in exchange for their work as slaves.
Was then when the time traveling Samaritan changed history, erasing the nightmarish future and also Infidel dominion. With the timeline having changed in 1986, Infidel was arrested and jailed as a madman, but he escaped and travelled back in time to find the Samaritan. Trying to restore his dominion, the Infidel travelled back to 1962 to manipulate the world into nuclear destruction during the Cuban Missiles Crisis. But the Samaritan was still there - just like the Infidel had remained when the XXXVth century was retconned. The Samaritan found and defeated the Infidel, then undid the 1962 manipulation.
Since then Infidel and Samaritan had fighting each other trying to change history but always surviving because both share the power of the empyrian fire, the energy than flows from time.