Technologically advanced humanoids who subjected Kirk, Spock and McCoy to cruel trials to test the compassion of an empath named Gem.
The Vians are a technologically advanced humanoid species with large, domed heads. Their devices let them manipulate matter and energy on a vast scale, and they show little hesitation in inflicting suffering on others when they believe their goals justify it.
In The Empath, the Vians Lal and Thann conducted experiments in the Minara system shortly before its star went nova. They captured Kirk, Spock and McCoy and tortured them to test the compassion of Gem, a mute empath, in order to decide whether her people deserved to be saved. Moved by her willingness to sacrifice herself, they relented.