T'Cael Zaniidor Kilyle was a protagonist introduced in the Star Trek original series novel Final Frontier.
A Romulan male, he spent the first part of his life as an officer within the Romulan military, and eventually rose to the rank of Field Primus Romulan Imperial Fleet. After meeting George Kirk, he decided to defect to the United Federation of Planets. Surgically altered to appear as a human, T'Cael adopted the alias Cale Sandorsen. Rising in the Federation diplomatic corps, T'Cael went on to set the standard for future Federation diplomatic efforts in the coming years.
