The gods of the Marvel Comics universe are a group of extra-dimensional superhuman beings that have been detrimental, responsible and indirectly influential toward the development of human civilization. There are well over a dozen apparently separate tribes or races of extra-dimensional superhuman beings known to humanity who claim to be gods, none of whom is God, the religious concept of the unique creator-force and guiding spirit in the universe prevalent in Judeo-Christian and Muslim faith. Gods appear to be a class of superhuman beings unto themselves. Because their origins and true natures are shrouded in myth and controversy, the gods remain difficult entities to readily define.
There are certain commonalities among all gods, an examination of which may shed more light on their special nature. All gods are or were physical beings and appear to be composed of something analogous to flesh, bone and tissue except that it is more durable, denser, stronger and more resistant to injury than similar human flesh, bone and tissue. Certain gods now exist in an immaterial state or can assume an immaterial state at will, but even these beings were once physical in origin.
No god exists alone, but is part of a tribe (called "pantheon") that includes numerous other gods possessing humanlike familial relationships with one another. Some pantheons include a number of gods known to the mythology of modern Earth and a large number who are not. Each pantheon is associated with a certain tribe, race or culture of people (usually kept isolated from other regions by geographic or cultural barriers) with a common origin who once worshipped them. Often times, a pantheon of gods is known by the group of people who worshipped them; for example, the Olympians have been known as both Greek and Roman gods, the Annunaki as gods of the Sumerians, Babylonians and Assyrians, the Danaans as the gods of the Celts and Gauls and the Coati by the Aztecs and Mayans. Each pantheon, as a self-contained group, sometimes took the name of the realm where they existed, a common ancestor or another reference to assign themselves as a race into their own, such as the Asgardians, Danaans, Xian or Anasazi. Each pantheon once existed or still exists in its own separate world and with certain exceptions (such as Hercules, Thor and other gods with vested interest in mortals), takes very little active part in the affairs of present day humanity. It has been suggested there are more than a few gods who have taken human roles or identities in history and have had parts in critical historical events. In fact, several gods have once lived on Earth in human roles (certain Egyptian and Sumerian Gods ruled as kings or pharaohs of portions of Earth before known written history). Without such direct contact, it is difficult to account for the strong connections between a given tribe of men and its corresponding tribe of gods, or for mankind's detailed accounts of the gods' activities (which later passed into myth). It is quite likely, that the gods of earth had vested interest in the destiny of human civilization and were elevated willingly or unwillingly into religious deities depending on their inherent personalities. In fact, several of the original concepts of mythology concerning the gods support the existence of one true deity or "God" before worship of multiple deities became widespread.
Certain individual gods within each pantheon became associated with a particular natural phenomenon, object existing in the natural world or much-valued skill. For instance, Thor is the Norse god of thunder, Artemis is the Greek goddess of the hunt and Horus is the Egyptian god of the sun. It may be happenstance that some skill or aspect of a god's nature was singled out for worship by the associated human tribe, but each human tribe has a god to correspond to all of the forces and attributes that are culturally significant to it. Mankind's worship of the gods does not appear to affect a given god's (or pantheon's) existence or store of superhuman energy. (This contrasts with demonic beings such as Dormammu, who will often drain portions of the life forces of their worshippers to increase their own power). If this were the case, a god such as Thor who has very few active worshippers today could not be as powerful as he is if he were dependent on belief in him to sustain his might. The relationship between ancient mankind and these extra-dimensional beings they called “gods” seems to have been one based solely on religious belief and peace of mind even long after the these gods ceased seeking active worshippers. In fact, long after many of them retired their godly duties, the continued with vested interest in the lives of their former worshippers and the descendants of such. Both Zeus and Hercules watched closely over their mortal descendants and Brigid of the Celtic Gods protects over the descendants of the Celts. In modern years, many of the former gods of Earth seem to traffic Earth but do so from behind mortal guises and restraints.
All of the pantheons of gods have their own myths of creation (which once believed by their human worshippers), assigning members of their pantheons with key positions in the creation of all that exists. Obviously, not all of these origin tales can be simultaneously literally true, and current scientific knowledge tends to discredit all of them. What is known about the origins of the gods is that they are not the first beings of their type to appear on Earth. There is substantial evidence that prior to mankind's existence, and perhaps the existence of any other relatively complex organic life on Earth, beings referred to as the Elder Gods once existed on Earth. These Elder Gods are believed to have somehow coalesced out of the Earth’s biosphere (the fertile life-supporting environment) and taken physical form by intermingling with the substance of the Earth itself. The first such being believed to attain consciousness in this way is called the Demiurge, and is the prime creative force of its kind. According to certain accounts, the Demiurge congealed into consciousness even as the conditions on Earth became right for life and then sensing the need for diversity, split up into countless fertile fragments, each of which spawned a new organism. These Elder Gods, the spawn of the Demiurge, were generally an imperfect class of non-humanoid beings (such as Set who took the form of the serpent), who degenerated into life-preying demons with the passing eons. The Elder God known as Gaea is believed to have escaped that fate by attaining a more advanced form (humanoid) and entrenching herself in the crust of the Earth itself. She thus became one of the few surviving Elder Gods and became known as Mother Nature. Gaea claims to have mated with a reincarnation of the Demiurge at the peak of the Elder Gods’ degeneration and given birth to a newer, more perfect race of gods.
Their offspring Atum was conceived to slay the degenerate gods of the old generation and open the way for the new gods of Earth. If Atum is indeed the first of the new gods and Gaea’s account of the Elder Gods is essentially true, then Atum is the primal parent of all the later pantheons of gods known to man. After slaying virtually all his predecessors and cleansing the earth of their evil, Atum split into countless fertile fragments, such as the Demiurge allegedly had done eons previously, thus spawning the modern races of gods now known to modern man. (Atum is the name the Egyptians called the primal Earth god. He may have been called other names by other pantheons). If Atum did spawn all of the pantheons known to man, then the individual gods of those pantheons are related even as all the families of man are related. (Indeed, the Egyptian gods viewed the Asgardian God Odin as the reincarnation of Atum.) Evidence of common ancestry among all the gods of Earth is that there have been intermingling between pantheons, particularly those whose worshippers have lived in close proximity to each other (such as the Romans and the Celtics). There is also evidence that what is now known as one tribe or pantheon is made up of more than one smaller tribe who merged together at one point. (For instance, the Aesir and the Vanir remerged into the Asgardians after years of unrest while the Coati have split into Aztec and Mayan Gods). Although this theory of the origin of the gods cannot be fully verified, it is as yet the most integrated hypothesis proposed to account for the many facets of the gods on Earth.
It would appear that none of the pantheons worshipped by the myriad peoples of Earth is an outright fabrication on the parts of their worshippers. Every pantheon once worshipped on Earth appears to have been (and in most cases still is) literally real. Among the many pantheons of gods known to exist are those beings worshipped by the Greeks and Romans, Norse, Egyptians, Mesopotamians, Hindus, Chinese, Japanese, Aztec and Mayan tribes, Incas, Celts and Gaels, Slavs, Finno-Ugrians, Native Americans, Oceanic Aborigines and Africans. The chieftains or "sky-fathers" of these various pantheons have encountered each other at various times, once at a convocation initiated by Odin of the Asgardians and Zeus of the Olympians to address the problem of the Celestial visitation on earth. (It should be noted that some of these pantheons have multiple sovereigns or chiefs in equal positions of power. Vishnu, Brahma and Shiva have shared rule of the Hindu gods and The Dagda and Leir are but two chiefs in the Celtic-Gaul Pantheon). It has been conjectured that it was the alien Celestials who dispatched at least some of the realms of the gods into other dimensions. Another theory is that the gods themselves elected to move their homes to other dimensions where they would be safer. Still another is that the godly realms naturally drifted into other dimensions due to a shift in the Earth's cosmic axis. (Virtually all the known godly realms have the cosmic axis manifested within it in some way.)
It should be noted that there are various beings who claim to be gods or were mistaken for them in the past, but are not truly gods. Among them are Eternals (Zuras was mistaken for Zeus), aliens, and mutants.