The original “Lord of Light”
Some Game of Thrones fans might be surprised to find out that the original “Lord of Light” was one of two Gods in a religion which almost beat out Christianity for dominance in the Roman Empire – and beyond. Manichaeism was a religion started by a man named Mani in Persia in the 3rd century C.E. (A.D.) It was heavily influenced by Zoroastrianism, Gnosticism and Buddhism, and he assimilated early Christian beliefs into his system. It lasted into the late Middle Ages and still has some adherents today.
Mani solved the philosophical/theological problem of evil by postulating that there is not one deity, but two: God (The Lord of Light) and the Devil (The King of Darkness), who are equally powerful. The problem of evil is, briefly, this: If God is good and omnipotent, then why is there evil in the world? Since God and the Devil are equally powerful, there is no more philosophical/theological problem of evil – evil exists because it is as powerful as God. According to Mani, the history of the world is the history of the struggle between the forces of good and evil.
It's interesting to note that (Saint) Augustine was an accomplished Manichean before being converted to Christianity. And, since Augustine was a seminal figure in Western Christianity, you could say that Christianity was itself heavily influenced by the “original” Lord of Light.