As a toddler, D'tannen's home in Morrowind was raided by a cult of Vampires that worshiped Molag Bal. All adults in the village were made into thralls for the cult, and the children began the process of being raised to one day join the cult as members. Similar to the Dremora philosophy, within the Vampire cult, power is regarded as the ultimate authority. To be weak and fearful is a shame worse than death. To care for others outside of their use to you is weakness, and interferes with self-preservation.

After years of rigorous training and indoctrination, D'tannen was finally inducted to the cult at age 26, where he faithfully served the cult and Molag Bal's will for 48 years.

Seeing the interest The Prophet held in Azaryne, and their subsequent escape, Molag Bal made an offer to the vampire cult: If someone were to bring Azaryne back to Coldharbour, permanently, they would be cured of the weaknesses of vampirism while maintaining all of the strengths. D'tannen eagerly volunteered.

D'tannen excels at almost every type of armed combat due to his upbringing and training in the Worm Cult. Despite using a staff mostly in his early encounters with Azaryne, one of his favored weapons is a pair of daggers.

After their journey into Orsinium, he receives a hand-forged maul as a gift from Azaryne which becomes his primary weapon choice from then out.