God

"Any sufficiently advanced technology is indistinguishable from magic."

- Arthur C. Clarke

A God is a supernatural, typically immortal being which is worshiped or respected by one or more group of believers. While the existence of one or more Gods remains subject of debate in the real world; Gods and God-like aliens have often being depicted as real entities in science fiction; whilst sometimes non-"supernatural" aliens will make use of superior technology to become worshiped as gods by more primitive cultures. It is also possible to equate the two situations using one of Arthur C. Clarke's laws that states that any sufficiently advanced technology is virtually indistinguishable from magic. The belief in pantheism consist of the idea that the Universe itself is God.

"Real" and mythological gods

 * Cthulhu (more correctly a demi-god, as a Great Old One), worshiped by the Spawn of Cthulhu (At the Mountains of Madness) and by Humans (The Call of Chthulhu).
 * Several other entities collectively known as the Great Old Ones (demi-gods) and the Outer Gods (such as Yog-Sothoth and Azathoth) in H. P. Lovecraft's fiction.
 * The entity from Robert Sawyer's Calculating God.
 * The Firstborn from Arthur C. Clarke's Space Odyssey series.
 * The Hitchhiker's Guide to the Galaxy series by Douglas Adams mentions God as a real entity, though noticing that the existence of the Babel Fish provides pretty strong evidence against him, and that he may have already vanished in a puff of logic. Also mentioned in the series are: Almighty Bob (worshiped by the Lamuellans), the Great Green Arkleseizure (worshiped by Jatravartids), Rob McKenna (worshiped by the clouds), and Thor, God of Thunder (in addition to the other Asgardians and Olympian gods).
 * Barry is a deity worshiped by the Melmacians. Apparently, after their 233rd birthday all Melmacians must choose between becoming ministers for the cult of Barry or becoming outcasts.
 * In Valérian and Laureline comics, there are beings which seem to correspond to, and identify themselves as, gods. They live on the mystical world of Hypsis: a planet which is constantly changing location around spacetime. Each small group of gods is responsible for a number of star systems. The three gods responsible for Earth assume the appearance of a middle-aged man, a younger man who claims to be his son, and a clock-like robotic entity. They seemingly represent, respectively: the Abrahamic God, Jesus Christ and the Holy Spirit.
 * The Tosoks worship a female entity known solely as "The God".
 * The Waldahudin are polytheists, believing in numerous gods, including some pretty unusual ones like the God of Alluvial Deposits.
 * The star Sol, seen from the Cheela's homeworld Dragon's Egg in the eponymous book by Robert Forward, was worshiped as an omnipotent god called Bright by the early Cheela civilizations.
 * The Boov believed that God existed as all water, and refer to the mass pollution of the ocean as God's "death".
 * The Chronomyst from Ascendancy worship a god called Chronos. The Frutmaka, from the same game, worship the god Graveesha, a personification of the black hole that exists near their home planet.
 * Logar is a mystical god worshiped by the Trions of the planet of Sarn, as seen in Doctor Who serial "Planet of Fire".
 * The Mentors worship the god Morgo, as seen in the Doctor Who serial "Mindwarp".
 * Ti is a god worshiped by the Deons, a religious sect of the Tigellans from the Doctor Who story "Meglos".
 * The Goddess of the Delvian Seek is an entity worshiped by the Delvians in Farscape.
 * The Sleestak from Land of the Lost are known to worship a creature, referred by them as a god, which lives in the bottom of a mist-filled pit. Although never seen, only heard, at least one episode contains hints that the monster is indeed supernatural.
 * The Spirit of the Abyss is a deity worshiped by the Magog.
 * Beings of the Warhammer 40k Universe often have their own gods, usually patron to a single species.
 * Most notably, the demonic Chaos God s are entities of Chaos, and are ruled across the galaxy by numerous species, though their chief worshipers are humans. Most species rightly and forcefully stamp out any Chaos worship, unless their society gets overtaken and they embrace Chaos. Beside the "Big Four", there are lesser Chaos Gods and divine quasideities, though the exact numbers can only be guessed at. The Chaos Gods are all rivals, and some species and organizations are dedicated to worshiping one particular god, though some worship Chaos as a pantheon or as different aspects of a higher being, whereas some are "secular" in that they spurn worship of any gods while still being steeped in Chaos.
 * Humans mostly worship Emperor, the founder of the Imperium of Man and now known as the God-Emperor of Mankind, who was an enigmatic, ancient, and immortal posthuman in life. After suffering mortal wounds, he is kept "alive" by arcane technology of his own devising, allowing his soul to obliquely interact with his followers and operate machinery critical to the continuation of the Imperium, though his physical body is quite dead, if suffering quietly. Much speculation about the Emperor's current state is hotly debated, and has caused holy wars and infighting amongst the Inquisition and the state church. Though he acts as the god of humanity, many believe that He would need to be allowed to fully decease to completely apotheosize (though this runs the risk of leaving humanity rudderless and incapable of FTL) or to reincarnate; others believe that he is still acting within his own plans, and to tamper with it would be heresy, a position maintained by the church. The Emperor is seen by his followers and enemies to be the chief antagonist to Chaos.
 * The Adeptus Mechanicus, a sub-empire of the Imperium and its "Institute" of technology, are given the right to their own faith. They hold a strange and animistic faith revolving around technology, headed by the Machine God. The Machine God is unique in WH40K, in that it appears to be wholly mythological. This may be because, though fervent, the Techpriests are cold and rational in their devotion (though "rational" being a variable term here), or it may be because the Machine God was inspired by the C'tan Shard trapped underneath the surface of Mars, a secret that very few know about. The Adeptus Mechanicus and Imperium are held together in that the physical representation of the Machine God is an entity named the Omnissiah, officially recognized as the Emperor.
 * Eldar had their own pantheon, though these were killed off with the birth of the Chaos God Slaanesh. Two survivors of their old pantheon are Cegorach and Khaine, fled and survive in their own ways and demesnes, though a third survivor, Isha, remains captive to Chaos, if theology and legend are correct. A fourth god, Ynnead, the Eldar God of the Dead, is incubating and is speculated to arise once the Eldar die out, though its followers are trying to change this. The Eldar pantheon is still given homage by the Craftworld Eldar and Exodite Eldar, though towards the end of their empire, they also had the secular "Dark Muses", a saint-like system of Eldar who excelled at and epitomized a specific discipline. Paying reverence to the Dark Muses contributed to the weakening of the Eldar Gods, ensuring their defeat by Slaanesh. Dark Eldar still utilize the Dark Muse system, though Khaine is still highly regarded, and Ynnead has a growing following.
 * Ork s worship worship the twin Gods Gork and Mork, thought to be god of "Kunnin' Brutality" and "Brutal Kunnin'" respectively. These two gods infight as much as they work together, reflecting Orks' tendency to fight amongst themselves once they run out of enemies.
 * Necron s paid heed to the C'tan, physical gods of the material universe, but realized that the C'tan feeding on them. After a great deal of conflict, the C'tan were destroyed or broken into "Shards", lesser beings though still incredibly powerful, and most shards were captured. A handful of C'tan shards remain at large, even millions of years after their initial destruction.
 * Tau are officially secular, giving credence to the philosophy of "the Greater Good," a social system that has a number of parallels with Confucianism in that it sets standards of behavior and provides a template to build a society from. Muddying matters and to their great consternation, the Greater Good does apparently have a representative warp entity, not unlike gods of other faith systems.
 * Tyranid s don't have any gods per se, but their collective conscious forms the Tyranid Hive Mind, a monstrous and alien overmind in its own right. The Hive Mind isn't worshiped, instead it simply exists as long as the Tyranids survive and a a critical mass of Tyranids is reached to allow for it to manifest. It provides direction for the Tyranids in the large and small scale, directing Hive Fleets and allowing the greater Synapse creatures to direct their smaller, more animalistic peers.
 * The Old Gods from the SCP Foundation multiverse. A loose pantheon of eldritch beings that influence the multiverse and it's inhabitants. Members of this pantheon include:
 * The Scarlet King:
 * Yaldabaoth: Almighty but mindless and blind deity who "devours" the gods, planets and stars and then "breathes life" into cosmos.
 * Mekhane: A technological god of machines who is worshipped by the Church of the Broken God and other sapient races of extraterrestrials such as the Mechanion and Taronyu. He is described as a massive winged humanoid consisting of many mechanical and technological body parts.
 * Hanged King:

Faux gods

 * An unnamed evil entity at the center of the Milky Way Galaxy claimed to be God in Star Trek V: The Final Frontier.
 * Q also claimed to be God in the Star Trek: The Next Generation episode "Tapestry", where he guides Picard in his near-death experience.
 * The Dalek Emperor was worshiped as a god by Daleks who survived the Last Great Time War in Doctor Who.
 * Yautja were treated as gods by ancient South American cultures on Earth in Alien vs. Predator.
 * Behemecoatyl, the Brain of Brains, is worshiped as a God by all of the Arachnids.
 * The alien known as Magus also claimed to be God in the Space: 1999 episode "New Adam, New Eve", but was revealed to be using technology to fake his powers.
 * The Builders, a mysterious old species which created the Leviathans from Farscape, are worshiped as gods by their creations.
 * Monarch from the Doctor Who serial "Four to Doomsday" believed himself to be God, and planned to go back in time to the creation of the universe to rendezvous with himself.
 * Akhaten is worshiped as a god by the inhabitants of the Sun-singers of Akhet, as seen in the Doctor Who episode "The Rings of Akhaten".
 * The Minotaurs from Doctor Who typically pose themselves as Gods by psychically manipulating, and feeding off, the faith of other creatures.
 * A mutated giant squid called Kroll is worshiped as a god by the Swampies on the moon Delta III from the Doctor Who serial "The Power of Kroll".
 * The Minyans from the Doctor Who serial "Underworld" believed the Time Lords were gods when they first encountered them.
 * The Menoptera from Doctor Who were worshiped as deities by their wingless descendants, the Optera, before the two species were reunited.
 * The artificial intelligence Xoanon is worshipped as a god by Leela's people in the Doctor Who serial "The Face of Evil".
 * The Yargonian leader, Yargo, genuinely believes himself to be a god and is worshiped as one by his people in Jacqueline Susan's Yargo.
 * In Halo the Forerunners were worshiped by the Covenant as gods but they were actually just a much higher advanced civilization.
 * The Erloors are worshiped as gods by the native humans of Mars in Gustave le Rouge's 1908 sci-fi novel Le Prisonnier de la planète Mars.
 * Those with the Goa'uld symbiotes in Stargate, known as the System Lords, force primitive civilizations into slavery, using various technologies from across the universe to enforce their will and illusion they were indeed gods. Many of them take on the persona of many deities throughout Egyptian, Greek and even Asian mythology.
 * The Changelings or Founders of the Dominion in Star Trek, are worshipped by everyone in their empire, such as the Vorta and Jem'Hadar as gods.
 * On the planet of Jekuul, which orbits 2 yellow suns, Kryptonian criminal and former General Dru-Zod, his wife Ursa and their son Lor-Zod are worshipped by the inhabitants as gods, due to their powers.
 * The Maykrs from Doom Eternal consider themselves gods, mostly due to their extra-dimensional origins and high advances in technology. Maykrs are capable of bestowing upon mortal beings such as Doom Slayer, with powers and abilities that make them godlike.
 * A member of the First Born, named Issus, was worshipped by all other inhabitants of Barsoom (Mars) as the goddess of life eternal and death, mother of the nearer moon and daughter of the lesser moon. It would later be revealed the she was nothing more than an extremely long-lived Black Martian, meeting her end when her followers tore her apart.