During the 23rd century, Keniclius 5 lived on the planetPhylos, where he continued to search for the perfect specimen for his master race designed to bring peace throughout the galaxy. He was regarded as "master" and "savior" by the Phylosian people.
Keniclius 5 cloned Spock Two into existence from the original Spock's genome. After Spock Two saved his predecessor's life by restoring the prototype Spock's mind, James T. Kirk and Spock 1 were eventually able to convince Keniclius 5 to change his work's focus to the restoration of the Phylosian civilization. (TAS: "The Infinite Vulcan")
In the script for "The Infinite Vulcan", Keniclius 5 is described as "a giant human, twenty-five feet tall." It is also stated in the script, "When Keniclius speaks, it is AMPLIFIED to give the sense of a giant speaking." The novelization of "The Infinite Vulcan" (as published in Star Trek Log 2) describes Keniclius 5's height as being "just under twenty-four feet."
In the non-canonical reference book The Worlds of the Federation, mention is made of the original Keniclius, and Phylos II, as it is called, is identified as being a Federation member, but Shane Johnson's text laments that "it is unknown whether the race will survive."