Dimiter Yen was born in Zantium. As a teenager he trained to become a paladin and was knighted when he came of age. At some point he married Octavia. They have no children.
After surviving the fall of Zantium, he left his wife behind in Melekess while he traveled the world, working as a witchhunter, exorcising spirits and engaging in kassiyadin, or spiritual warfare. He eventually retired and settled down to become a priest at Nykara Chapel in Melekess. Taking the holy vows required that he commit to pacifism; thus, he could no longer call himself a paladin. He became Watchman Dimiter Yen.
Years later, Dimiter rescued Leonard Gorrister from a group of thugs who were trying to rob him. He carried Leon to the safety of the chapel, where he tended to his wounds. After learning that Leon was looking for the paladins, Dimiter revealed his past and reluctantly agreed to take him to Marcus for training. While he initially refused to participate, Dimiter did eventually teach Leon some martial arts techniques, though his real expertise was in kassiyadin, a concept which baffled the young apprentice.