Perhaps the predominant religious component is the series’ theme: the human survivors’ search for Earth. That search is motivated by ancient religious texts’ references to a 13th tribe of humans that established a civilization on a distant planet called Earth. Various religious relics and ruins on the Twelve Colonies and elsewhere in the galaxy provide clues to Earth’s location. Throughout the series, humans and Cylons are assisted in time of need by mysterious entities, possibly from a higher plane of existence.
Many of the humans practice polytheism, worshiping the Lords of Kobol. This appears to be the state religion of the colonies; government oaths refer to the gods, and back on the Twelve Colonies, public museums housed artifacts of the gods. Some people are devout believers, others are atheists, and most fall somewhere in the middle; all three viewpoints are accepted more or less equally.
The Kobol gods have the same names and characteristics as the Greek Olympian gods and the show makes references to Zeus (as well as Jupiter), Hera, Athena, Poseidon, Ares (as well as Mars), and Apollo. As evinced by prayers offered by the human characters, the Kobol gods are morally refined and are believed to watch over and intervene benevolently in the lives of the just. This is similar to the concept of the gods during the Greek classical and Hellenistic periods, not the amoral (and very human) gods of the Greek archaic period. In another parallel to Western polytheism, the names of the Twelve Colonies and their planets are similar to the names of the constellations in the Greco-Roman zodiac. The finale implies that the Greek and Roman pantheons, as well as several ancient belief systems including the zodiac, were imported to Earth by the colonial survivors.
The principal means of transmitting divine knowledge are the Sacred Scrolls. The Scrolls chronicle the early period of human existence, when people and the gods purportedly lived together on the planet Kobol, whose location at the beginning of the series is unknown and is regarded as mythical by secular humans. The Scrolls tell that at some point in time, twelve human tribes left Kobol and founded the Twelve Colonies, while a thirteenth headed towards Earth. This is also referenced in the opening words of the Scrolls: “Life here began out there.”
The show offers few details of the Sacred Scrolls. One important feature mentioned is the Book of Pythia, which chronicles an ancient prophetess (similar to the Oracle of Delphi named Pythia) who journeyed with the Thirteenth Tribe on their voyage to Earth. Pythia also described the exodus of the other Twelve Tribes, and the things that happened to them. She describes a dying leader who would guide the tribes to salvation. President Roslin sees herself as playing the part of the leader in the texts, as she has terminal breast cancer. Another important quotation from the scrolls is the recurring phrase “this is not all that we are,” a phrase considered the foundational statement of faith.
At times, Hinduism is referenced in the series as well. The opening credits are accompanied by a New Age-inflected version of the Gayatri Mantra, a hymn dedicated to the solar deity Savitr. In addition, during a memorial service scene, the residing chaplain recites an important Hindu prayer, a sample from the Brihadaranyaka Upanishad.
Many of the Cylons also share a religion. It differs greatly from the humans’ religion; it is monotheistic and shares many beliefs of Abrahamic monotheistic religions (God is omniscient, omnipotent, omnibenevolent, that he will one day deliver divine retribution and that he intervenes in the world). The different Cylon models have varying degrees of faith; at least one, Cavil, does not subscribe to any religion. Some humans have come to follow the Cylon religion, mostly by way of Gaius Baltar, who himself grew to believe in the Cylon religion through the efforts of “Caprica Six”.
Battlestar Galactica continued from the 2003 miniseries to chronicle the journey of the last surviving humans from the Twelve Colonies of Kobol after their nuclear annihilation by the Cylons. The survivors are led by President Laura Roslin and Commander William Adama in a ragtag fleet of ships with the Battlestar Galactica, an old but powerful warship, as its command ship. Pursued by Cylons intent on wiping out the remnants of the human race, the survivors travel across the galaxy looking for the fabled and long-lost “thirteenth” colony: Earth. Unlike most space opera series, Battlestar Galactica has no aliens (the antagonists are man-made Cylon robots), the primary armaments used by both military forces utilize bullets, rail guns, and missiles instead of lasers, and the series intentionally avoids technobabble. Instead, most of the stories deal with the apocalyptic fallout of the destruction of the Twelve Colonies upon the survivors, and the moral choices they must make as they deal with the decline of the human race and their war with the Cylons. Stories also portray the concept of perpetuated cycles of hate and violence driving the human-Cylon conflict, and religion, with the implication of a “God” whose angelic agents appear to certain main characters (most notably Gaius Baltar).
Over the course of the show’s four seasons, the war between the Colonials and the Cylons takes many twists and turns. Despite the animosity on both sides, the humans and a faction of the Cylons eventually form an uneasy alliance, in the wake of the Cylon Civil War. The Cylon leader, humanoid Cylon “Number One” named John Cavil precipitated the schism in the Cylon ranks. Cavil deceives the other models by obsessively hiding the identities and origins of the remaining five humanoid Cylon models, the “Final Five”, who, known only to him, are a more ancient type of Cylon, created by a previous iteration of human civilization. Other plotlines involve the mysterious destiny of Kara “Starbuck” Thrace, who is the subject of a prophecy claiming that she is the “Harbinger of Death” who will “lead them all [humanity] to its end,” as well as the redemption of Gaius Baltar through the Cylons’ monotheistic religion, after he becomes a pariah within the fleet.
In the final episodes, an inexplicably resurrected Kara Thrace leads the surviving humans and their Cylon allies to a new planet, which Adama names “Earth”. The first group of survivors settle in ancient Africa. The “real” Earth that the Colonials had searched for during their years in space was revealed in an earlier episode to have been originally inhabited thousands of years before by a previous form of humanoid Cylons; the “Final Five” were the last of these Cylons. Ironically, these humanoid Cylons created their own Centurion robotic slaves, who waged a nuclear attack against their masters, devastating the planet and making it uninhabitable. The new Earth is found to be inhabited by early humans, who are genetically compatible with the humans from the Galactica and the rest of the fleet, but who possess only the most rudimentary civilization. Human beings had apparently evolved independently on both Earth and Kobol, the original home world of the humans who settled the Twelve Colonies.
The surviving humans and humanoid Cylons settle on the new planet; they discard all technology, destroying the fleet by flying it into the Sun, in order to postpone the creation of robotic servants until their society has progressed to higher ethics. The surviving Cylon Centurions are given possession of the remaining Cylon Basestar, and proceed to jump away from Earth. In the final scenes, modern-day Earth humans are shown to be descendants of the colonists, their humanoid Cylon allies, and the early humans.
At the end of the series finale, an angelic Baltar and Cylon Number Six (played by Tricia Helfer) are walking down a sidewalk in modern-day New York City. They are unseen and unheard by the people around them. As the two walk, they notice technologically advanced robots, computers, and other cybernetic devices, and they talk about the technological advancements the humans have made since the Colonists and Humanoid Cylons first arrived to this Earth, over 150,000 years earlier. Cylon Number Six and Baltar have an exchange over one of the on-going themes from the series, “All of this has happened before. But the question remains, does all of this have to happen again?”