backdoor programs to shut down the network and its defenses. The thermonuclear attacks wiped out billions of humans, nearly the entire colonial population. Two Battlestars – Galactica and Pegasus – survived. A fleet of civilian ships was scattered throughout the neighboring space. Together they fled into deep space. The Cylons pursued them while initiating the next phase of their evolution, procreation. Female human survivors were detained and used in experiments to create Cylon-human hybrids. The experiments were unsuccessful leading the Cylons to conclude that the missing component was love. They tested this by using an Eight posing as Lt. Sharon "Boomer" Valerii from Galactica to seduce a marooned Galactica officer, Lt. Karl "Helo" Agathon on Caprica. They fell in love. The Eight abandoned the Cylons, helping Helo to escape. The couple later produced the first viable human/Cylon birth. This Eight joined the fleet with Helo. She later married Helo, joined the Colonial military and received the call sign "Athena". Ten months after the initial attacks, Eight Sharon Valerii (call sign "Boomer"), attempted to assassinate Commander Adama under the influence of programming unknown to her. She was unaware that she was a Cylon before the attack, though she had been uneasy because of unexplained blackouts (during various attempts to sabotage Galactica). A vengeful crew mate, Cally Henderson killed her. She downloaded into a new body and settled on Cylon-occupied Caprica in her former apartment, unable to relinquish her human identity. She led a campaign for better treatment of the humans. She and other like-minded Cylons influenced the Cylon civilization, which withdrew from the colonial home worlds and pursued benevolent treatment of the humans and then reconciliation. During this time, the half-human half-Cylon hybrid, Hera Agathon was born on Galactica. Fearing that the Cylons might capture the child, President Laura Roslin faked Hera's death and secretly had her adopted by a human woman. New Caprica The humans settled on a harsh and barren planet they dubbed New Caprica. The refuge lasted a year before the Cylons found them. Outnumbered and outgunned, the Galactica, Pegasus, and the rest of the colonial fleet in orbit were forced to flee, leaving the Cylons to occupy the human settlement unchallenged. Initially the occupation was peaceful, but later the Cylons became more forceful and vicious in response to increasing human Resistance. In the end they used punitive methods to keep the humans in line, including summary executions