Sten was a Vulcan male of the 23rd century. Originally betrothed to T'Prynn in his childhood, Sten's fiancée later refused marriage. Refusing to allow T'Prynn to disregard her pledge, Sten invoked the Vulcan practice of koon-ut-kal-if-fee. An especially proficient combatant, T'Prynn was able to defeat Sten; a bitter victory at best, as Sten's katra managed to force its way into T'Prynn's mind where it remained to torment her. (VAN novel: Harbinger)
Sten's katra was eventually removed by the Healer Sobon and placed into a vre'katra. (VAN novel: Open Secrets)