Le'or was a member of the Taelons species who held a rank within the Synod. His existence was uncovered after the apparent destruction of the Taelon race when the Atavus re-emerged on Earth. The Atavus leader Howlyn probed the mind of Ronald Sandoval to learn of the Taelons previous attempts at conquering mankind and learnt of the use of Cyber-Viral Implants. On one such occasion, he leant of a Human named Jack Malley who bonded with the Taelon Mothership.
Afterwards, Howlyn had Malley's CVI implanted in his brain and accessed the mothership that recognised him as Le'or as a result thus resulting in the Atavus leader gaining full control of the Taelon vessel. (Episode: Art of War)