A God Emperor is a sovereign who is claimed, either by self or others, to be a Physical God. This trope can apply to anything from a tinpot tyrant with delusions of grandeur to a Galactic Conqueror or Dimension Lord with perfectly accurate assessments of grandeur.
Note that this means that if the character in question is not claimed to be a god that disqualifies them from this trope even if the ruler is godlike in power.
Given its extreme usefulness in either helping found new religions or unify the recently-conquered into new nations, this trope is Older Than Dirt, and long a staple of fiction or fact.
Compare with Emperor Scientist and Sorcerous Overlord, which is how a good many of them get their start; and The Emperor, to whom the God Emperor trope may apply also. Compare Priest King, when the ruler is head of both Church and State, but not worshiped themselves.
In Real Life, declaring themselves gods has been very common to the rulers in ancient history. It handily brought religious and secular power together, and gave the ruler an absolute power, which was always welcome. The Egyptian pharaohs are the most famous example of the trend. Note that this shouldn't be confused with the divine right of kings, which was a doctrine holding that kings derive their authority directly from God. This gives similar advantages but acknowledges that the king himself is mortal.
If you're looking for an emperor/king/leader of the gods themselves, see King of the Gods.
Ancient Belka from Lyrical Nanoha had the next best thing to a God Emperor, the Sankt Kaisers, who claimed to be, saintly (while it is yet uncertain whether the Sankt Kaisers were worshipped in their time but the modern Sankt Kaiser Church on Mid-Childa is built around worshipping the last one) and wielded magical powers close to that of a Physical God. For a comparison, an untrained, six-year-old clone of the last Sankt Kaiser went toe-to-toe with one of the strongest Aerial Mages on Mid-Childa, and would have defeated her eventually, had she gotten serious. Considering that with her final Power Limiter removed, Nanoha scores S+ on the aerial mage ranking scale, it would put Vivio and the other Sankt Kaisers at least into SS zone (something that only Hayate has achieved so far, but Hayate's SS is only a composite rank), with the potential to reach SSS (the highest possible ranking) with sufficient training.
Emperor of Darkness, Big Bad from Great Mazinger (the first Mazinger Z sequel) was emperor of all Mykene and in later retellings it was stated he was Hades, Greek God of Underworld. Given that the Mykene were an ancient Greek civilization lived underground, it fit.
The kings of The Twelve Kingdoms. Ruling a kingdom comes with such perks as immortality and the ability to speak and understand any language. (Or at least Chinese, Japanese and whatever language is spoken in the Twelve Kingdoms) and quite a few very nice palaces. The downside is that if they rule badly the kirin who chose them to rule in the first place will begin to sicken and die, which means they will die sooner or later as well, along with the weather and youma running wild in the kingdom. If the king doesn't change their ways the only way to avoid this is to step-down from the throne and commit suicide.
Mind you high ranking civil servants and even their own servants also get immortality and language ability, so those aren't unique to the kings. And they don't have to worry about answering to Heaven the way kings do.
Father from Fullmetal Alchemist could qualify as this, as he manipulated the country of Amestris since its inception, after obtaining immortality and immense powers from sacrificing an entire country to make a Philosopher's stone.
In Naruto, after Pain seized control of Rain, he was both its ruler and widely regarded as a god by his shinobi.
Soul Eater has a low-key example in the form of Lord Death. Few questions that he is most powerful being there is, he wields tremendous executive authority, and has done so for thousands of years. From Death City, he commands international paramilitary forces that can cross any border and attack any target without interference. That said, he tends not to meddle much in the affairs of people who aren'twould-be Kishin, Witches,Weapons, Meisters, or engaged in the production or use of Magic Tools. The only reason Death City exists is because Lord Death sealed himself to that location in order to lock down Asura the Kishin ("demon god"), a former member of the Grim Reaper's right-hand men who turned himself into a monster Death wasn't sure he could kill. Now the Grim Reaper can't leave the city, even if Asura were to escape. This is why he got himself a son (somehow), to eventually replace him as a fully-mobile Guardian of Life and Souls.
Eneru from One Piece claims divinity, and has power to back it up. Within his domain he knows all, he can smite anyone from the heavens. He is physically invulnerable. He can travel at will instan1taneously, meaning he's nearly omnipresent too. His official title is, in fact, God. However,it turns out he's just using a variety of super powers technically available to anyone with the right results in the Superpower Lottery, and the title of God is just what they call all their kings. He's totally insane.
Ghaur, high priest of the Deviants, at first connives to take over from the king of Lemuria and after doing so calls himself Priestlord, but when he hijacks the powers of the Deviants' god, a Sufficiently Advanced Alien Celestial, he upgrades himself to Godlord. And keeps the title even after losing said power.
The Ultimate Marvel version of Thanos is both god and king of a star-spanning empire.
Darkseid. As he says in The DCAU, "Here [on Apokolips], I am God." "Darkseid is."
Charon from Negation. Bonus points for Charon ruling the entirety of his universe and it's his official title.
The Joker became this in the Emperor Joker arc in Superman, where he managed to gain Reality Warper powers by stealing them from Mister Mxyzptlk. In a similar manner to Kefka Palazzo from Final Fantasy VI when he ascended to godhood, the Joker ravaged the world and turned it into a twisted parody where he could commit all the murder that he wants, including devouring China or killing Batman and Luthor over and over again. Eventually, he decides to destroy all existence so someone like himself would never exist. Thankfully, he managed to stop himself when Superman points out that Batman is what defines him.
ElfQuest's "Kings of the Broken Wheel" story arc has the human warlord Grohmul Djun declaring himself this after the Palace of the High Ones crashes in his territory post-timeskip and "spirits" (elves and trolls both) start to make their presence known, in order to keep his subjects from getting ideas about him somehow not being the ultimate authority and lord of all he surveys. It doesn't really help for long.
Stargate: Galactic Imperium. Not shown in either of the series, Area 51 has a computer scientist, Dr. Kevin Leed. Well, his alternate reality self got his hands on An'ran's reality jumping device. And he's got the collective knowledge of the Tok'ra. And he's a bit power-hungry. Result: he decides to use his extensive sci-fi knowledge to infiltrate the Odyssey, copy the Asgard core, steal Atlantis' database then create a huge empire spanning multiple universes. Oh, and did I mention he's a huge fan of Warhammer 40,000?
Stargate: Golden Dawn. Amann Adar of the Alesian Empire is a half ascended being that could crush entire battalions of enemies with little effort. Any of the Alesian Council in this story is this trope really.
The one time Kuei demonstrated his power, he kicked the Knowledge Spirit Wan Shin Tong, one of the Embers' universe's power players and all of his kitsune agents out of the Earth Kingdom. No wonder everyone prostrated themselves before him except the Fire Nation refugees. Even they went to one knee.
The Nostalgia Critic stood at the army's forefront, dressed in a uniform to rival the greatest generals of the ages. A peaked cap sat upon his brow, marked by a winged insignia of great power and vanity. His cape flowed down to his knees, colored grey like the skies underneath which he was born. A polished chain linked the two lapels of the cape together, and it shined under the Nevada sun like gold mined in neighboring California. Underneath his cape he wore an armored bodysuit of crimson and ebon black, which reached all the way down to boots that reached to his mid shins. He wore white gloves accompanied with silver gauntlets that cradled his forearms of average girth. This was no longer a mere critic. This was a god in human form.
Queen Of Shadows: The Shadowkhan view their Queens as divine, due to them being the only ones capable of creating more of their race (the fact that the original Queen was an actual demigod probably helps with this opinion of them).
Persian King Xerxes in 300 known as the God-King. This doesn't hold up well, because while his men successfully wipe out the Spartan 300-man unit, Leonidas cuts his face by throwing a spear at him, utterly humiliating the so-called "God-King."
The sequel, 300: Rise of an Empire, indicates that Xerxes really is a supernatural being, although it's unclear whether that translates into any specific abilities other than being really, really tall and talking like a Goa'uld.
Starship Troopers 3: Marauder reveals the Bugs' supreme leader, Behemecoatyl, who is explicitly referred to as the "Bug God".
Queen of the Damned. Like the Pharaohs, the first vampire Queen Akasha was seen as a God-Queen when she ruled over Ancient Egypt.
The goal of the protagonists in The Man Who Would be King is for one of them to achieve this status, by finding a remote and relatively primitive society and playing on their superstitions to be thought supernatural beings.
Dune. God Emperor Leto II, the first of the two standard Trope Codifiers. Also possibly the Ur Example of the construct-title of "God-Emperor", at least in the English language.
The titular Emperor Mage from the third book of Tamora Pierce's The Immortals series banned sacrifices/offerings to the gods, saying that if people wanted to make sacrifices, they could make them to him instead, as he has more direct power over their lives. Eventually this pissed off the country's Trickster patron deity, and the shit really hit the fan... bottom line, Don't Try This at Home.
The Lord Ruler from Mistborn. And God-King Susebron from the same author's Warbreaker though he's much more god than king, being a figurehead whose primary purpose is to be worshipped, rather than to actually run the state.
Also from Mistborn: The Original Trilogy, God Empress Vin. Though it should be noted that she became a God and an Empress separately and in two different ways.
In David Eddings' Malloreon cycle (the sequel of The Belgariad), it is revealed that the emperors of Mallorea are divine per definition, due to the original emperor being a LITERAL God, Kal Torak. The emperor thus holds the official name of 'Kal Zakath', and becomes a major character... but at the end of the book, he changes the policy and drops the 'Kal' (Which is Mallorean for God-King, in case you didn't guess), actually crossing it out in an official letter because, as he puts it, "Now that I've seen some REAL gods in action, it just seems ostentatious". That said, he was never entirely thrilled with it from the outset and only took it because his administrators were so worried the empire would fall apart after Torak's death they wouldn't stop on about it until he did so. It wasn't until he saw the real gods in action that he finally climbed out of his apathy enough to put his foot down and get rid of it.
In the Dragonlance novels and Dungeons & Dragons campaign setting, the last Kingpriest, Beldinas Pilofiro, tried to turn himself into this. It didn't work so well.
The Autarch Sulepis of the nation of Xis in Tad Williams' Shadowmarch series is regarded as a living god, with absolute control over his vast empire and designs on ruling the world. Also once ordered a man to be tortured to death in his library so he could read and listen to his screams at the same time.
The Acts of Caine gives us His Most Beloved, the Ascendant Ma'elKoth, who fulfils this trope until being sent to Earth at the end of Heroes Die. After the climax of Blade of Tyshalle, he abandons the Physical God aspect and just becomes a nonmaterial deity, leaving the Emperor bit to Deliann.
Although the God Emperors from The Stone Dance of the Chameleon begin life as mortals, when they ascend the throne they undergo apotheosis, at which time their blood turns into pure ichor.
The Eternal Emperor of the Sten Chronicles books fits the profile pretty well.
Lanfear's plan is to set herself and Rand up as God Emperors using the infinite powers which they have by using the Choedan Kal to overthrow the Dark One and then challenge the Creator.
Rand himself becomes a small-scale one of these, binding several countries under his leadership (and keeping them loyal through the use of his magic powers—he is the strongest spellcaster who has ever lived) and forging alliances with the ones he does not dominate outright. It reaches the point where, even ignoring his tremendous magical abilities, he is the most powerful person in the world through the sheer number of nations he holds in thrall.
In the last book it's revealed that Demandred is more-or-less one of these in The Empire of Shara, having taken on the persona of Bao the Wyld, He Who Is Owned Only By The Land, the dragonslayer. The prophecies he followed to attain this position are heavily implied- and confirmed by Word of God- to parallel the ones about Rand. His followers practically worship him, and their morale is shattered when he dies.
In R.A. Salvatore's Forgotten Realms novels, King Obould Many-Arrows is blessed by the orc god Gruumsh with divine power. His subjects begin to see him as the physical incarnation of Gruumsh on the mortal plane, referring to him as Obould-Who-Is-Gruumsh. He gives little actual weight to these ideas, keeping a fairly realistic assessment of his limitations, but uses the moral that belief in him inspires as a tool to establish the first stable, recognized orc state. Ironically, given how he didn't actually believe he was a Physical God, after his death he Ascended To A Higher Plane to become a literal (demi)god.
The Godkings from The Night Angel Trilogy. The people of Khalidor literally believe them to be gods. The Godkings themselves know they're not gods, but they tend to behave like they think a god would to fool their people. The first and last one was pure evil and they groom their children to be just like that.
Moses, Man of the Mountain has this, both with the obvious example of the Pharaoh, and with Moses himself, who is seen like this by the Hebrews. He's somewhat disturbed by this, as he does not see himself as a god or a king.
The Supreme Overlord of the Yuuzhan Vong from the New Jedi Order, while not considered to be on par with the Yuuzhan Vong pantheon, is certainly regarded by his followers as something greater than mortal, and apparently has the powers to back it up. Said powers turn out to be the doing of the realBig Bad, the Supreme Overlord's deformed, Force-using jester Onimi.
In the Retief story, "The Hoob-Melon Crisis", the Groaci ambassador to an empty planet declares himself king, since there's no one around to dispute the claim, and then manages to use the argument of the divine right of kings to get himself accepted into the official Groaci pantheon as a God, since he was the one who made himself king.
Subverted in the Books Of Swords and Books Of Lost Swords series by Fred Saberhagen: the Emperor actually is God. It's just that the Emperor isn't the secular ruler of anywhere, and most people think he's just a wandering clown and mountebank.
In Saberhagen's earlier trilogy The Empire of the East, set thousands of years earlier in the same world, this is played straight with Orcus, mightiest of all the demons and founder and ruler of the eponymous empire, until he was overthrown by his right-hand man, John Ominor.
While normally just a badass emperor, Richard of the Sword of Truth briefly becomes this in the last book of the Chainfire trilogy, but gives it up after he's made the changes he thinks are necessary.
In A Study in Emerald by Neil Gaiman, Queen Victoria (not to be confused with the historical queen of the same name) is technically a Great Old One Empress, but as far as her subjects are concerned, there is very little difference.
John Carter of Mars: Issus, ruler of the black Martians, is known as a goddess even beyond their realm. Actually she's just an old crone without any special powers, which the blacks are so angry to find out that she doesn't survive it.
The ruler of Fiona Patton's Branion is this — the monarch of an alternate Britain and the Vessel of a fire God's power. Book 3 revolves around the faithful trying to get the throne back when the royal family converts to another faith and denies its own divinity.
The Shaggat Ness from The Chathrand Voyages is an interesting one. The Mzithrin Empire is normally ruled by an alliance of five kings (hence why it's also known as the Pentarchy) but forty years before the series began King Ness, one of the five, suddenly went mad, proclaimed himself Shaggat (Mzithrini for "King and God") and launched a massive crusade to become ruler first of the Mzithrin, and then the world. The other kings put his rebellion down and he fled, only to be captured by the rival Empire of Arqual, who faked his death and imprisoned him on a remote isle with the intention of one day returning him to his still-fanatical worshippers in order to weaken the Mzithrin at a critical moment. Ness himself remained absolutely convinced of his own divinity and scarily charismatic for an Ax-Crazy maniac, even convincing his Arquali prison warden, who held him in terrified awe. It later turns out that it was Ness's advisor Arunis who convinced him he was a god, as the first step of an elaborate plan to kickstart the apocalypse.
In M.C.A. Hogarth's Flight of the Godkin Griffin, the Godkindred believe that cross-species breeding will enable them to ascend to godhood, and that their ruler, the Godson is closest to that goal. It turns out that he actually is a god, but apparently from sheer force of will rather than breeding, and after Angharad destroys his physical body by channeling the power of Shraeven's disembodied gods his spirit remains as the kingdom's patron god, with Angharad as his Priestess-Queen somewhat ironically.
Nicolae Carpathia claims to be this in the Left Behind book series during the Tribulation, and Jesus Christ is simply this during the Millennial Reign.
The Dalek Emperor that ruled during the Time War started styling itself as "The God of the Daleks" after it rebuilt them as religious fanatics loyal to it.
Davros tried to become this, with his creations the Daleks as the supreme rulers of existence and he as their master, but unfortunately he was too Genre Blind to recognise the logical conclusion of a non-Dalek trying to rule a species deliberately designed to hate anything not like them.
Emperor Cartagia didn't think he was a god yet, but he believed he could ascend to godhood and become a God Emperor with his dealings with the Shadows.
Subverted in an early episode when Londo asks Vir how many gods there are in the Centauri pantheon. Vir is unable to give him a clear answer because so many of the Empires numerous emperors have declared themselves Gods.
The Goa'uld System Lords, who pose as Gods. In fact, most of them actually buy their own propaganda.note Pretty much the only one who doesn't is the Dangerously Genre Savvy Baal, who's rather flippant about his godhood when speaking to those who already know the truth. The primitive people they enslave and oppress believe them to be gods, however.
Also, the Ori, ascended beings who masquerade as gods in order to gain worship from people who don't know the truth. Unlike the Goa'uld, though, they can actually back up their claims of divinity, being able to alter matter with a thought, create life, and having technology several thousands of years beyond anything almost anyone else has (the Asgard excepted.)
Highlander had an immortal who got into this in 'Little Tin God'. He killed the previous immortal ruler of a South American tribe and set himself up as "the decapitator". The people bought it because when he killed other immortals, it produced the light and sound show of the Quickening.
Lexx: His Divine Shadow, a succession of hosts to the essence of the last of a race of planet-sized insects who ruled an entire universe (one of two).
MythQuest: Alex temporarily becomes Osiris, an Egyptian god who unified Egypt and became the first Pharaoh.
Mythology & Religion
Most codified monotheistic religions give this, or close enough, as one of the myriad titles of its given subject deity.
The Yellow Emperor being accredited with the invention of traditional Chinese medicine, he supposedly found the secret to Immortality and so, his "death", at the end of his supposedly 100-year-long reign, was supposedly just him ascending to heaven atop of a dragon. Well, that's not to mention that he was actually worshipped for a time.
The Immortal God-Emperor of Mankind, the second of the two standard Trope Codifiers. Funnily enough, unlike other examples he specifically said he wasn't a godnote past tense is crucial; he's almost certainly a god now and wanted to create a society of Flat Earth Atheists (supposedly to starve the Chaos gods of their required sustenance). But after the Horus Heresy happened, he was immobilised and stuck on life support for ten thousand years, and the Imperium became a totalitarian fanatical nightmare, which was his last demand before being put into the throne, since he realised that the Chaos Gods feed more on emotion than prayer.
Sigmar in Warhammer was also deified after he disappeared. His religion became the offical religion of the empire and a major political force (they have three votes for who gets to the emperor) much to chagrin of Cult of Ulric who used to be the major power (they even crowned Sigmar).
Daemon Princes, in both 40K and regular Warhammer. After achieving the ultimate power of Chaos, they spend the rest of eternity mostly ruling over their followers and shaping their own corner of the warp to their liking.
Iuz the Old in the Greyhawk campaign setting. As an actual demigod he rules his realm as a literal God-Emperor and most of the functionaries running things are his clergy.
The God-Kings of Mulhorand in the Dungeons & DragonsForgotten Realms setting. Before the end of the Time of Troubles, Unther was ruled by an avatar of Gilgeam, the last god of the Untheric pantheon that neither was dead nor had bolted for another pantheon (or just plain bolted — for reasons to do with interplanar magic and an interdict on divinities, the Mulan gods had to keep their avatars on Toril to keep a link to the world). He was not a good ruler, especially not at the end, but he was the only thing keeping an ancient peace treaty between the Mulhorandic and Untheric pantheons - and therefore between Mulhorand and Unther - valid...
Though neither were actually gods, the Scarlet Empress and Solar Queen Merela both had strong elements of this trope, particularly in the power department. Also, a common term for First Age Exalted rulers in general is "god-kings". And, this being Exalted, it is entirely reasonable for the player characters to have attaining this status as one of their long-term goals.
Given the nature of the powers of the gods and the Exalted, Exalted are powerful enough that apotheosis would be a step down in rank.
While many Exalted can be god-kings in principle, the Zenith Caste of the Solars (and their Abyssal and Green Sun Prince counterparts) exemplify it (at least in so far as some can blur the line between priest-king and god-king, though all are made to be kings).
Exalted can get worship from mortals, which has a host of benefits.
Malfeas has settled on the upper edge of this power belt after his post-War castration. Before that? He had so much power, he couldn't be constrained by a physical form. And the beings he ruled made the gods. And the world. And then kinda got rolled for their lunch money by the Exalted and shoved into hell.
The Emperor of Rokugan is not a god, but does have literal divine blood due to being directly descended from the original gods of the sun and moon. The first dynasty was founded by their youngest son Hantei, but after the fortieth Hantei emperor died without an heir the throne was taken by the former Lion Clan Daimyo Toturi, himself a direct descendant of the sun and moon's eldest child Akodo.
Taken further in that all of the great clans are ruled by direct descendants of the sun and moon, most of them founded by one of their children. The Mantis Clan, which was granted Great Clan status more than a thousand years after the founding of Rokugan, was still founded by a great-grandson of the sun and moon.
The Shadowlands to the south was long ruled by another child of the sun and moon, Fu Leng.
In the Dragonlance novels and Dungeons & Dragons campaign setting, the last Kingpriest, Beldinas Pilofiro, tried to turn himself into this. It didn't work so well.
Iron Kingdoms gives use Lord Toruk the dragonfarther, all mighty ruler of the Nightmare Empire of Cryx, he happens to be a Godzilla size Dragon/ Eldritch Abomination that wants to kill everyone and turn them into zombie robots.
Razmir the Living God in Pathfinder, ruler of Razmiran. The text explicitly states that he is a charlatan, but the players may or may not know this.
The Lord of Blades in the Eberron campaign setting for Dungeons & Dragons is a Warforged who hopes to lead a kingdom of his race to subjugate the humanoids that created them, and some Warforged clerics pray to him for spells.
The One King of the Firstborn of Tabletop Game/Chronopia, he was all powerful being who liberated humanity from being enslaved by the Blackbloods, Elves, and Dwarves. He was onced killed by the Devout, but his soul went to the other side and fought the Devout's god the Dark One. He defeated the evil god and came back to life to lead his people.
The Dominions series revolves around this concept in a more literal fashion. Every player takes on the role of a pretender god, very powerful creatures and mages that are making a bid for God-hood, now that the former Pantokrator is gone. This Pretender is represented in-game as an actual unit. You even get your own religion, temples and priests! One particular Pretender type, the Divine Emperor, goes double by being a literal emperor who managed to use the fact that he's technically the Son of God (due to Roman-style post-death deification of emperors) to leverage himself into Pretender God status.
A downplayed example: The Dark Elves worship the Tribunal, a trio of living, flesh and blood gods. In the modern day they exert great influence, but aren't officially the government and their powers have waned greatly; rather, there's a separate King of Morrowind, who reports to the Emperor. But before Dagoth Ur's return and the Imperial conquest of Morrowind, they really did fit this trope.
Tiber Septim, the first Emperor of the Third Era, he achieved apotheosis and is worshipped by Imperial citizens as Talos, one of the Nine Divines. He has an especially strong following in the Legion.
While Talos, as the Ninth Divine, is the most prominent of the post-death apotheosized Men, at least two other rulers got the same: Cuhlecain, Septim's predecessor (Tiber was his general, and took over and continued the work when Cuhlecain was assassinated) with 'the Cult of Emperor Zero' and Reman Cyrodiil, founder of the Second Empire (also known as the Worldly God and the Light of Man).
In Skyrim worship of Talos has been banned thanks to a humiliating treaty forced on the Empire by the fascistic AldmeriDominion. One in-universe book speculates that he was originally three seperate men, one a Body Double of the others, who upon becoming one at the end of Daggerfall, Talos rewrote the past to become a single living demigod in the past.
The Overmind, for the rest of the Zerg, in the original StarCraft; all the more so given the fact that every Zerg, especially the Cerebrates, were manifestations of different aspects of his/its personality.
Kefka Palazzo also became this in Final Fantasy VI. Basically, he was technically already made Emperor after he betrayed and murdered Gestahl, but when he also absorbs the Warring Triad's power during the year of his reign, and even by the time he moves the Triad out of alignment, he pretty much became God and Emperor.
Legacy of Kain: "Kain is deified. The Clans tell tales of Him. Few know the truth. He was mortal once, as were we all."
Touhou has Suwako Moriya. In a reversal of how this trope usually goes, she started as a Mountain Goddess, then became the ruler of what would become the kingdom of Moriya. Somewhere in there, she single-handedly tamed the Curse Gods of the land. Suwako defended her kingdom from other gods who wished to conquer it, until she was tactically outmaneuvered by Kanako Yasaka, a Wind Goddess, to whom she surrendered. Kanako then become the God-King of Moriya, but the humans and Curse Gods didn't accept her, so she had to settle for joint-rulership with Suwako. This arrangement worked out very well for everyone involved, and continued until the twilight of human faith in the modern era, at which point Kanako decided to move herself, her old friend, and her friend's half-goddess descendent into Gensoukyou to gather new faith.
Pretty much what the Black & White series is all about, but reversed. You play a disembodied god making your wishes known through supernatural means.
In Fallout: New Vegas, Caesar's Legions view of Caesar himself is best stated around here, with them believing he is the son of Mars and a God. This goes a long way to explain their fanatical devotion to the Legion. Caesar himself has no such delusions, but his ego is no less massive.
Dark Souls has Gwyn, Lord of Sunlight. The leader of the various godly Lords and father of several gods on his own, he rules over man from Anor Londo in Lordran.
Shao Kahn of Mortal Kombat, while not specifically referred to as a god, he's a powerful, apparently ageless warlord of a Death World; in 9 he proclaims himself to be one near the end and before the Timey-Wimey Ball, it's revealed he had won Armageddon and achieved omnipotence. His predecessor, Onaga, though very mortal, was also extremely powerful, and displayed power over life and death. When he died his army allowed Onaga's holy men to mummify themselves alive so they could serve again if he returned.
The Last Remnant has a man who they call the God Emperor, who ruled the land for a long time before the start of the game. By the start, however, his power is only relegated to the area he lives in, as everyone has developed into monarchy-like city-states, leaving him God Emperor In Name Only.
The World of Warcraft contains several individuals who may fit the requirements to be considered God Emperor:
First we have the founder and (not acting) leader of the Burning Legion, Sargeras. He originally was the greatest warrior of the titans, who was appointed by them to hunt down and imprison all the demonic races who sought to prey upon the ordered worlds they had created. After killing one too many demons and seeing one too many races corrupted by them, he went mad and decided that universe itself to be fundamentally flawed and that it must be destroyed and recreated anew without imperfection, for which effect he released all the demonic races he had imprisoned and gave them the option to help him destroy the universe or be killed by him, guess which one they chose. Due to the fact that he could probably destroy Azeroth single handledly, he was Put on a Bus, by banishing his spirit into the Twisting Nether following his corruption of Medivh, which didn' stop the legion from carrying on his mission, and his Dragon Kil'Jaeden taking command in his name, but never trying to usurp command, simply considering him to be "absent". Though he has godlike powers, he doesn't seem to encourage his minions to worship him, but mortal groups like the shadow council, who seek the favor of the legion, do so anyway . There's also the widespread belief among the community he will be the final boss of the final expansion of WOW, so how can he not be godlike if his death signals the end of the verse.
Thrall himself is a borderline case as he gave up his Warchief Mantle(read: stopped being an emperor), before gaining proper godlikepowers in the third expansion. Technicalities aside, some orcs(who were at the time not members of the horde, and arguably had no idea how powerful can you become with proper training in WOW) expressed doubts that he could be mortal upon seeing him for the first time, so that would probably count as "worship".
Lorewalker Cho: Would that we could all live like our most sacred emperor. That we could put aside all our burdens and exist in harmony with the cosmos.
Raidriar the God King from the Infinity Blade series is a self-proclaimed example, though he is merely one of the Deathless, albeit one of the most powerful. According to Galath the Worker of Secrets, Raidriar is unique in that he is the only Deathless who genuinely believes he is a god. The others never forgot their original human roots and merely pretended to be divine to rule over humanity.
Bahamut, god and king of dragons, in 8-Bit Theater, who rules by his own divine mandate. Several characters remark that it must be a pretty sweet job and is probably something you have to be born into.
Lt. Pibald from Schlock Mercenary is not a God Emperor, but claimed to be one on one of his dozens of applications for the demolitions expert position. Petey seems to be closer to the mark.
Sluggy Freelance: At the end of one story, it seems that alternative reality America is about to elect the Goddess of Goodness their president. You can't even refer to her without calling her a goddess. Her enemy the Demon King of the Dimension of Pain is also at least heavily implied to be a god by his subjects, particularly when he's pointedly worshipped as an evil Crystal Dragon Jesus in one guest story.
Recurring villain Kelelder the Planet Thief in Jix is an immortal Ambis who assassinates nobles and claims their planets for fun, and is worshipped as a god by a legion of loyal followers. And it seems he's planning to make the "emperor" part official by adding the Ambis emperor to his trophy wall.
Seems to be the most common form of government in the Tales of MU universe. The emperor of Magisteria (the America equivalent) is unique in being a mere mortal, while the Nameless One that the founder of his dynasty rebelled against is still alive.
Diamanda Hagan, ruler of Haganistan, actually has a pretty good case for divinity. Thus far, she's risen from the dead three weeks after committing suicide just to see if she could, possessed several other internet reviewers, come back from the dead again, and transformed a minion into an unused vibrator in its original packaging using the power of her mind. Supernatural powers aside, it's also implied throughout the first couple seasons that she's a genius—and given that omniscience is also a part of godhood...
The Captain ie. the Star Stalker (past life of Tennyo) from the Whateley Universe "ruled" a major star system thousands of years ago, and became deified after she disappeared.
My Little Pony: Friendship Is Magic: The two princesses ruling Equestria, Celestia and Luna, come really close, but it's implied rather than stated. They are the stewards of day and night, respectively, and control the associated celestial bodies. Phrases such as "thank Celestia", "in the name of Celestia", and "as Celestia as my witness" have been used, hinting the ponies themselves view her as divine as well as regal (Luna is just less well known, to make a long story short). All that's missing is anyone actually calling them "gods", a word that has never, ever been used in the show.
Japanese emperors before 1945. Usually though, Japanese emperors always claimed descent from Amaterasu, but playing at being a Physical God really only happened under the fascism within parts of Hirohito's reign.
Invoked by the Roman emperors who were Genre Savvy enough to follow the lead of Augustus, the first emperor, and leave orders to deify them after death.
Including perhaps the most Genre Savvy, Vespasian, whose dying words were 'I think I am becoming a god', a direct reference to the apotheosis of Emperors.
It has also been said to be one of the reasons for the whole problem with Christians: as they only had one god, they didn't accept the divine nature of the emperor, who in turn didn't accept them. On the other hand, once most Roman Citizens were Christians, the practice of Caesaropapism began, in which Imperial decree gave legitimacy to the ecumenical councils that he called in the first place to try to end all the squabbles that were messing with Imperial unity.
Gaius Caligula jumped the gun and started when he was alive: he even wanted to put his statue in the Jewish Temple in Jerusalem! You can imagine how well that went over. The funny thing is, he thought he was being nice: every other religion had a statue in its Holy of Holies, so he figured the Jews must just have been too poor or something to deck out their Temple properly. His response to this was like, "I know! I'm a god—and I've got way too many statues lying around! Here! Have one! Wait, you don't want a statue? Weirdos." (Truth be told, most of the Mediterranean didn't really get the whole "thou-shalt-make-no-graven-image" thing.)
Generally the worse an emperor is depicted as being in our sources the more likely it is that they will state that he claimed to be divine while alive (the other obvious candidate being Commodus, of Gladiator fame). State worship of the Emperor in Rome was generally considered a big no-no throughout the Empire's existence. Outside Rome was another matter.
Despite common belief as 300 might lead you to believe, the Persian King-Of-Kings was not worshipped as a God, as the Persians were monotheistic Zoroastrians. The misconception arose among the ancient Greeks, who mistook the Persian practice of proskynesis before the monarch for an act of divine worship, when it was in fact a secular social ritual.
Kim Il-Sung and his son Kim Jong-Il "rule" over and are "worshipped" in North Korea. (Note the present tense for both "rule" and "are worshipped". Though Kim Il-Sung died in 1994 and Kim Jong-Il in 2011, the elder Kim retains his position as "Eternal President" and the younger is still referred to as "Dear Leader" and "Eternal General Secretary of the Party".) The cult revolves around the elder Kim's revolutionary activities and the transformation of North Korean system.
Official North Korean history places Kim Jong-Il's birth at the foot of the holy mountain of Paektu, beneath a new star and a double rainbow. In fact he was born in in an army camp in Siberia. Official history also claimed that he played 38-under-par on his first try at golf and that he never defecated. He personally claimed he could create rain on command and that he invented the hamburger.
A few journalists have reported that they are directly worshipped, or at least prayed to. Nobody knows yet whether the new leader, Kim Jong-Un, will receive the same treatment.
Before the Republican revolution of the 20th century, Chinese Emperors were each known as the "Lord of Ten Thousand Years." Hong Xiuquan, who led the Taiping Rebellion against the Qing dynasty in the mid-19th century, called himself the Heavenly King and believed he was the younger brother of Jesus Christ.
A running theme in Thai history. Spend any time in Thailand and you will see people praying to icons of King Rama V. King Thaksin the Great went one better, and declared himself to be the reincarnation of the Buddha. (Which is shockingly blasphemous in Thai Theravada Buddhism: it amounts to denying that the Buddha achieved nirvana in death, at which point he would have stopped reincarnating, which basically denies that he was the Buddha.) The current King, Rama IX, has attracted his share of veneration, given that he is: a, the longest-serving head of state on Earth; b, reigned over the greatest expansion of Thai prestige and economic growth in history; and c, is listed on this very wiki on the Cool Old Guy page.
Meanwhile, in China, the rulers had what was called The Mandate Of Heaven, which basically means that as long as they made sure things were going well in the kingdom, they obviously had the blessings of heaven with them. However, when the emperor started caring more about his own pleasures than helping the people, and his officials started making life miserable for everyone, well, it was obvious that the Mandate Of Heaven was removed, and it was time to go kill the emperor, his lackeys, and anyone else who was doing a crap job of ruling the country, and put in someone competent. Of course the origin of the Mandate was from the Zhou Dynasty, whose first ruler made this to justify overthrowing the Shang Dynasty by claiming that the Shang also did this too.
This was of course very convenient, as it both gave justification for imperial rule (Heaven favors this person to run the country) while also justifying revolt and rebellion through explaining the corruption that dynasties inevitably suffer over time. The Mandate essentially condensed the historical pattern of inevitable disintegration of space filling empires in a controllable, constitutional form.
Despite not being considered a god (at least not in Ethiopia), Haile Selassie's full title was "His Imperial Majesty Haile Selassie I, King of Kings, Lord of Lords, Conquering Lion of the Tribe of Judah, and Elect of God". Meanwhile, he was (and is) considered the second coming of Christ by the Rastafarians. He was quite surprised (and perhaps disturbed on religious grounds, being Christian and the head of the Ethiopian Orthodox Church) to find this out upon visiting Jamaica in 1965. However, out of respect he didn't disabuse their belief.
Wilfried Daim published a photograph of a document signed by Adolf Hitler. This document ordered the "Immediate and unconditional abolition of all religions after the final victory", and proclaimed Hitler as the new messiah.
Many rulers (of both nations and religious sects, mostly Christian ones) play with this. They don't claim that they are Gods, but claim themselves/their blood line has been chosen by God, giving them a divine right to rule. After many political upheavals and the destruction of European Monarchies' power (plus thedegrading of royal linesfrom excessive inbreeding), most nobles refrain from declaring this notion openly anymore.