That's really a question for River of Souls, a short story (or book idk) that talks about how demandred became the leader of the Sharans. It was supposed to be included in a memory of Light, but it was cut because it hasn't been reviewed by Maria Simmons. However, Demandred is thought to be the second most accomplished man in the Age of Legends. If Lews Therin was the messiah for Randland, Demandred might be the messiah for a second, less powerful nation
