Thamior Amasticia is the half-elf son of the human Demarcus Amasticia, a wealthy trader from Waterdeep. Thamior was born of a scandalous love affair between his father and an eladrin, whose name is unknown. The mother abandoned both Demarcus and Thamior soon after his birth. Ashamed, Demarcus moved the child to Lantan, saying that it was for his son's education. In reality, Demarcus was attempting to restore the now-tarnished reputation of the Amasticia name.
Thamior spent many of his youthful years as a wanderer, traveling the eastern seas of Toril. His father begrudgingly continued to send money for an education that Thamior was wasting. Hoping to get is wayward son to show some responsibility, Demarcus placed Thamior in charge of the Amasticia's Lantanese shipping accounts.
Eventually, Thamior began conducting lucrative business with the Zhentarim, selling narcotics and powerful Lantanese alchemical weapons. Thamior quickly gained influence and power over other criminal organizations through the Zhentarim. Feeling unstoppable, Thamior pursued a romantic relationship with his long-time friend Annabelle Leigh Tarkio. Annabelle spurned his intentions because of his ties to a number of dubious groups.
Thamior blamed Zichew for turning Annabelle against him. Thamior and several hired goons attacked Zichew, but were defeated by a group of Gondsmen. Thamior was badly burned in the attack and has sworn revenge.
Recently Thamior has joined the Green Band, an organization bent on ridding Lantan of technology. Thamior has a personal agenda of ridding the world of Zichew. Thamior is also seeking pursuing Annabelle Leigh.