User with this ability either is or can transform into a Transcendent Being, existing in a state of being free from the constraints of the material world, as in the case of a deity or other beings that can/have overcome the limitations of physical existence and also be/become independent of it.
User is physically and mentally beyond essentially all forms of harm or other ways to influence them (outside of other beings of similar status, superior beings or some specific concepts), and gain powers that are supernatural to outside viewers. While they can enter into the material universe, becoming immanent, their true being is outside existence and thus both independent and outside of everything that happens to their manifested/avatar form.
As they are able to perceive existence in a completely different and transcendent way, they can achieve things that are beyond the understanding of lesser beings, for example, a children's toy built by them could be used as a dangerous, and unstoppable weapon by the lower races.
There is also different variations within godhoods, and they are split into three flavours:
Religion Focused: Deities of this category originate from sacred doctrines, especially the fact that there is a single SupremeBeing, which is basically the most powerful kind of God imaginable that created the entirety of existence. For example, God himself is a Trinity God, which is the purest and most accurate kind of Supreme Being.
Mythology/Folklore Focused: Gods of this category stem from myths, also alternatively referred to as legends and folklore. Greek gods can be the best example of those kinds of Deities. More often than not, there are Divine Lords, which are basically Gods that are immensely powerful over their kind, though not to the same echelon of power a monotheistic deity has.
Race Focused: Deities that are of this category, are associated with races (like animals, beings, monsters, aliens, and the whole nine yards), yet have godly influence over the specific kinds of races they exclusively belong to. Race lords, while they are immensely powerful, are not of this since they are not of, and just have powers that aren’t of godly status. However, what the race lords and race-focused deities have in common, is that they can both possibly be progenitors of the species they’re part of, and both are superior over their species. In basic terms, race lords are of course powerful, but no where near the same level as the race-focused gods. Unlike race lords, race-focused gods have physiological powers (and/or even abilities that their kin doesn’t always have in physiology terms), and most/all their racial weaknesses are stripped clean, therefore making them nigh-unbeatable until a reliable way of defeating them was discovered, like forcibly giving them weaknesses via powers, objects, etc, and/or removing their godhood, and possibly among others along those lines.
User with this ability can use the powers of a deity or deities from mythology. For example, if someone wanted to gain the power of Zeus, they would gain electrokinesis, aerokinesis, and (possibly) asterokinesis. While the user can become incredibly powerful once mastering this power, it also shares the same weakness as Mythic Physiology, and is limited by the amount of knowledge concerning the deities. Users with this power will be weaker than those who wield the "true" version of this power.
Ikusa-Tsunagi (Fairy Tail) is one of the 18 War Gods of Yakuma.
Chronos (Fairy Tail) is the God of Time.
Susanoomon (Digimon) is a divine and godly powerful Digimon.
As one of the very few Ultra-level Digimon in existence, Arcadiamon Ultra's (Digimon) sheer power suprasses that of even godly Digimon.
ZeedMillenniummon (Digimon) is an Evil God Digimon with the power to create and destroy time and space at will.
Huanglongmon (Digimon), the Yellow Dragon of the Center, is the leader of the Four Holy Beasts and has power comparable to natural disasters.
Lucemon X (Digimon) is said to be a perfect being with ultimate power and wisdom, transcending even God.
Goku (Dragon Ball series) as the Super Saiyan God
Beerus (Dragon Ball Super); the God of Destruction of the 7th Universe.
The four lower Kais (Dragon Ball), who guide life in the 7th Universe.
Grand Zeno (Dragon Ball Super) is the supreme ruler of the multiverse, and possesses incomprehensible power beyond that of any and all gods and angels.
The Grand Priest (Dragon Ball Super) is an angel who's power is second only to Zeno himself.
Sōsuke Aizen (Bleach) became an immortal Transcendent Being through the power of the Hōgyoku.
Ichigo Kurosaki (Bleach) is a transcendent being due to his perfect balance of Quincy, Shinigami, Hollow, and Fullbring powers, being a prime candidate to replace the Soul King and was even able to ultimately kill Yhwach.
The Soul King (Bleach) is the supreme being that sustains all of reality. Without it (or anyone possessing its power), all the dimensions would collapse on each other.
After killing and absorbing his father, the Soul King, Yhwach (Bleach) took its place as the linchpin of all reality, able to sustain and destroy all dimensions at will.
Gerard Valkyrie (Bleach) is the animate Heart of the Soul King, and possesses immeasurable power and is nigh-invincible.
Mimihagi (Bleach) is the animate right hand of the Soul King and has several godly powers, most notably Stagnation.
Pernida Parnkgjas (Bleach) is the animate left hand of the Soul King and has several godly powers, most notably Evolution.
Gremmy Thoumeaux (Bleach) is the strongest Sternritter, second only to Yhwach with power to alter reality according to his imagination.
Lille Barro (Bleach) is the first being granted power by Yhwach. At his full power, only a weapon designed to kill gods could hurt him.
Hikone Ubuginu (Bleach) is an artificial amalgamation of Shinigami, Hollow, Quincy and Fullbringer, with the intend to create the next Soul King.
Sailor Cosmos (Sailor Moon)
Chaos (Sailor Moon) using Sailor Galaxia's body as a host and becoming Sailor Chaos
The Harvest Goddess (Harvest Moon)
Aqua Regina (Mermaid Melody)
Kaguya Ōtsutsuki (Naruto) after eating a Chakra Fruit from the Divine Tree, became the first ever person to utilize Chakra to its maximum potential.
The Six Paths Sage Mode Transformation boosts all of Naruto Uzumaki's (Naruto) already impressive traits to their highest potential.
The Supreme Deity (Seven Deadly Sins), the leader of the Goddess clan.
Virgil, The Ring Lord (Saga Frontier) has absolutely no weaknesses, so much so that you can't even hurt him, the most you can do is entertain him with your attacks.
The Fierce Deity (The Legend of Zelda: Majora's Mask)
Chaos (Final Fantasy)
Kratos (God of War) a demigod who transcended to become a god of war.
Suwako Moriya (Touhou Project)
Chakravartin (Asura's Wrath), the nigh-omnipotent creator deity of the world, the embodiment of Samsara, and the source of all Mantra.
Asura (Asura's Wrath), having ascended to true godhood as Asura the Destructor, and possesses nigh-limitless power rivalling Chakravartin.
Yasha (Asura's Wrath) is one of the most powerful demigods, rivaling Asura.
DIO, Gone To Heaven/Heaven Ascension DIO (Jojo's Bizarre Adventure: Eyes of Heaven)
Ogre (Tekken), the God of Fighting
After receiving the Essence of Blaze, Ermac (Mortal Kombat) became a transcendent hive mind made up of the souls that were once contained inside him.
Raiden (Mortal Kombat) god of thunder.
Din, Nayru, and Farore (The Legend of Zelda), the three Golden Goddesses of Hyrule.
Hiruko (Valkyrie Crusade) is a extremely powerful goddess with mysterious origins.
The Everlasting Dragons (Dark Souls), a race of immortal stone beings that ruled during the Age of Ancients.
Gwyn, Lord of Sunlight/Cinder (Dark Souls), Lord and God to the people of Anor Londo.
Dark Sun Gwyndolin (Dark Souls), son of Gwyn, god and acting lord of Anor Londo.
Gwynevere, Princess of Sunlight (Dark Souls), daughter of Gwyn.
Gravelord Nito (Dark Souls), Lord and God to the people of Anor Londo.
The Witch of Izalith (Dark Souls), Lord and God to the people of Anor Londo.
The Furtive Pygmy (Dark Souls), keeper of the Dark Soul and progenitor of mankind.
Manus, Father of the Abyss (Dark Souls), creator of the Abyss.
At some point, the Old Iron King (Dark Souls II) found the Old King Soul - Gwyn's Reincarnated Lord Soul - exerting its influence across the land.
The Duke's Dear Freja (Dark Souls II) possesses the Old Paledrake soul - Seath's reincarnated soul - exerting its influence across the land.
The Rotten (Dark Souls II) possesses the Old Dead One Soul - Nito's Reincarnated Lord Soul - exerting its influence across the land.
The Lost Sinner (Dark Souls II) possesses the Old Witch Soul - the Witch of Izalith's Lord Soul - exerting its influence across the land.
Nashandra (Dark Souls II) is a fragment of Manus, Father of the Abyss' soul, granting her unspeakable dark power.
Elana, the Squalid Queen (Dark Souls II) is a fragment of Manus, Father of the Abyss' soul, granting her unspeakable dark power.
Nadalia, Bride of Ash (Dark Souls II) is a fragment of Manus, Father of the Abyss' soul, granting her unspeakable dark power.
Alsanna, Silent Oracle (Dark Souls II) is a fragment of Manus, Father of the Abyss' soul, granting her unspeakable dark power.
Aldrich (Dark Souls III), Saint of the Deep and Devourer of Gods, became an amorphous blob monster after divulging in devouring men, and was forced as a sacrifice to the First Flame for his might, becoming a Lord of Cinder.
Yhorm the Giant (Dark Souls III) sacrificed himself to the First flame, becoming a Lord of Cinder.
Ludleth of Courland (Dark Souls III) sacrificed himself to link the First Flame, becoming a Lord of Cinder.
The Abyss Watchers (Dark Souls III) sacrificed themselves to link the first flame, collectively becoming Lords of Cinder.
The Lord of Cinder (Dark Souls III) is the deific incarnation of every Lord of Cinder.
Great Ones (Bloodborne) are eldritch entities that ascended fro the earthly plane, becoming gods to the Pthumerians and the people of Yharnam.
Moon Presence (Bloodborne)
Lesser Amygdala (Bloodborne)
The Brain of Mensis (Bloodborne)
Ebrietas, Daughter of the Cosmos (Bloodborne)
Celestial Emissary (Bloodborne)
Mergo's Wet Nurse (Bloodborne)
Rom, the Vacuous Spider (Bloodborne)
The Orphan of Kos (Bloodborne)
After the Hunter (Bloodborne) slays the Moon Presence...
...he/she is reborn as an infant Great One.
The Dahaka (Prince of Persia: Warrior Within)
The Elder God (Legacy of Kain)
Wizeman the Wicked (NiGHTS series) is a god and the creator of Nightmare and the Nightmarens.