Cavil is first seen serving as a religious advisor within the fleet. He counsels Tyrol after Tyrol's nightmares have led him to breaking Cally's jaw. He surmises that Tyrol is worried that he is a Cylon.
Another Cavil latches on with Kara's rescue team on Caprica after the Cylons suddenly halt their attack and vanish. Caprica Eight (Helo's Sharon) clearly recognized him as a Cylon, but said nothing.
When Kara's rescue party returned to Galactica with Anders and the Caprica Cavil, Tyrol instantly called him out as a Cylon which Cavil admitted to.
The two Cavils ended up in the brig where the Caprica Cavil announced to Admiral Adama and President Roslin that the Cylons were ending their occupation and were going to stop chasing the fleet. The Cylons were going away to carry out some self-examination.
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