Cylon models
Six and Eight are the most common in the series. Two Number Eight copies are featured as central characters — Boomer and Athena.
Sharon "Boomer" Valerii Lieutenant Junior Grade Sharon "Boomer" Valerii is a
Cylon sleeper agent programmed with false memories of being raised in the mining colony Troy. Before the mini-series, Boomer and
Galen Tyrol are romantically involved. Her programming leads her to sabotage the
Galactica on several occasions, which Tyrol unwittingly abets by hiding evidence implicating her. In "
Kobol's Last Gleaming",
Commander Adama sends Boomer on a mission to destroy the Cylon basestar orbiting Kobol; upon her return, she shoots Adama twice in the chest, putting him in a coma and revealing her nature to the crew. While Boomer is being transported from the brig, Cally shoots and kills her. In "
Downloaded", Boomer's preserved consciousness is downloaded into a new body in Cylon-occupied Caprica. She resists being identified with the Cylon cause and tries to persuade the Cylons to reduce hostility against humans. In "
The Eye of Jupiter", Boomer attempts to care for Athena's hybrid child Hera on the Cylon base ship, where the child ended up after the New Caprica evacuation. In a conflict with the visiting Athena over whether the humans negotiated in good faith, Boomer is killed by Caprica Six for endangering the child. After resurrecting into a third body, Boomer develops a relationship with
John Cavil, a Number One who embraces his machine nature and sees human traits as a weakness. Cavil enlists Boomer's support when the Cylon models become deadlocked in a vote over whether the Raiders should be lobotomized. Boomer turns against Cavil during the Colonial assault on the Cylon colony. After returning Hera to Athena and Helo, who were part of the boarding party, Boomer is executed by Athena for her previous actions.
Sharon "Athena" Agathon Sharon "Athena" Agathon is originally created to impersonate Boomer and ensure the success of a Cylon experiment to create a Human-Cylon hybrid. She aids
Karl "Helo" Agathon on Caprica, intending eventually to kill him. However, she eventually falls genuinely in love with Helo and tries to help him escape, during which he both discovers her true identity and that she is pregnant with his child. Sharon uses her knowledge of the Tomb of Athena on Kobol as leverage to avoid immediate execution aboard
Galactica and consistently demonstrates her loyalty by defending the group from Cylon ambushes. Sharon's reunion with the
Galactica personnel is tense due to Boomer's history with them, but she makes it clear that she and Boomer are different people. Upon learning of irregularities in the pregnancy, President Roslin orders it terminated but rescinds the decision when Sharon's fetal blood is used to cure her terminal cancer. Sharon gives birth to her child prematurely and names her Hera. The Colonial administration decides it is too dangerous to let a hybrid child be raised by a Cylon mother, so they fake the child's death and rehome her with a human mother. Despite the strain this puts on Sharon's loyalty, she continues to help the
Galactica. Sharon and Helo are married in the gap between Season 2 and Season 3, and Sharon is recognized for her service by being sworn in at Boomer's rank of Lieutenant JG. She is sent back to New Caprica as the liaison between the
Galactica fleet and the resistance effort and is able to infiltrate the Cylon base and steal the keys for the civilian ships. After the successful rescue mission, Sharon is assigned to join the
Galacticas pilot corps with the callsign "Athena" after the
goddess of warfare and wisdom. During Colonial negotiations with the Cylons, Athena and Helo learn their daughter is still alive on a Cylon ship. Athena travels to the ship, retrieves her daughter, and honors Boomer's wish to be executed for betraying the Colonial cause. == Analysis ==