James T. Kirk, beaten by the thrall Shahna
Thrall was a term given by the Providers to the individuals of various species enslaved on the planet Triskelion. The thralls were later freed by Captain James T. Kirk's actions. (TOS: "The Gamesters of Triskelion")
A thrall is a slave, whether someone in physical, mental, financial or even emotional slavery. The term originated in the Norse culture of old Earth, in the region of northern Europe once home to the Viking. In its original context to be a thrall meant to be a slave or at best a serf, one who toiled exclusively for the benefit of a ruling class and who lived or died at their whim.