The Thrintun (singular Thrint), were a long-extinct species which ruled the galaxy through telepathic mind control from 3 to 2 billion years ago. Humans knew them as Slavers. The Thrintun (singular Thrint), in Larry Niven's fictional Known Space universe, are a long-extinct species that ruled the galaxy through telepathic mind control. They debuted in Niven's World of Ptavvs, in 1966.