Great Old Ones

That is not dead which can eternal lie,
And with strange aeons death may die.

Abdul Alhazred, The Necronomicon 

The Great Old Ones are ancient creatures of immense power, and most are also colossal in size. They are worshipped by deranged human cults, as well as by most of the non-human races of the mythos. The Great Old Ones are currently imprisoned—a few beneath the sea, some inside the Earth, and still others in distant planetary systems (and beyond). The reason for their captivity is not known, though there are two prevailing theories: They were sequestered by the Elder Gods for committing past transgressions, or they are sealed off somehow from the rest of the universe by their own volition.

According to the first theory, the Great Old Ones were once members or servants of the Elder Gods. When they committed some unknown blasphemy, they were cast out and imprisoned in various places in the universe. The Great Old Ones impatiently await the time of their release, eager to seek retribution against their jailors.

The second theory holds that the Great Old Ones are intentionally quiescent. To account for this, it is possible that the universe experiences cosmic cycles, similar to the seasons of the earth. Just as some animals hibernate during the winter, so too must the Great Old Ones rest in death-like sleep during the present cosmic cycle. If this is so, the Great Old Ones are currently trapped by powerful cosmic forces and must remain so until such time as "the stars are right"—the event upon which they are released and can revel once more across the cosmos.

Another theory suggests that the Great Old Ones have fallen into hibernation due to unsuitable conditions.

It is also possible that they are subject to some combination of the theories previously proposed.