Cwansi, born 2380 on New Thallon, was the son of Thallonian prince Si Cwan and human Starfleet officer Robin Lefler.

Shortly after his birth, Cwansi was kidnapped by Doctor Selar, who, in her desire to find a cure for her son's rapid aging, had allowed herself to be manipulated by an alien presence, who were later revealed to be cloning half-breeds. He was later rescued by Soleta and a repentant Selar. (NF novel: Treason)