Caleb was a ghost of the Terran Dominion before being recruited by Project Shadowblade. His identity was restored and thanks to terrazine exposure, his psionic powers intensified. He was the last ghost recruited to the program before Kath Toom.
During the Spectre Rebellion, he took part in a mission to Korhal Palace under the command of fellow spectre Gabriel Tosh. The mission was to kidnap Arcturus Mengsk. Caleb fought against the group of ghosts that defended Mengsk, but ultimately the spectres were turned back. Caleb was one of the spectres who survived the encounter.
Later, on Gehenna Station, Caleb announced the arrival of the Palatine with Nova Terra and Malcolm Kelerchian aboard. Ultimately the base was destroyed along with Project Shadowblade, though Gabriel Tosh managed to sneak off the station with six spectres in stasis. It is unknown if Caleb was among them.