The Great Old Ones (often simply referred to as the Old Ones) are a group of unfathomably ancient and incredibly powerful alien beings who ruled over Earth long before man or any other species lay claim to it. Aside from their cosmic origins, the Great Old Ones often do not share much of anything in common, coming in many shapes and (almost always colossal) sizes, with fundamentally different natures. Due to their awesome power and near-incomprehensible biology, they are worshipped by numerous lesser entities as gods. However, even the Old Ones, being infinitely beyond the pathetic beings mankind would consider worthy of such a title, are not truly "gods", for their impossible might is nothing next to the seething and chaotic Outer Gods, who are to the Old Ones what the Old Ones are to a three-dimensional race such as humanity, if not even more incomprehensible.
Without a doubt, the most well known amongst the Great Old Ones is the mighty Cthulhu, who slumbers in his city of impossible geometry beneath the ocean waves. However, it is suggested that Cthulhu is one of the least powerful Old Ones, being stated to only be capable of spying a faint glimpse of their true strength. Despite this, other Mythos stories introduce Old Ones who are on par with or inferior to Great Cthulhu, making it likely that, while certainly not the absolute weakest of the Old Ones, many of Cthulhu's "cousins" exceed him by a great deal. In fact, it is implied that the rest of existence can likely only spy them dimly as well, for the strongest of them exist unbound by the infinite dimensions of reality, allowing them to tread in a space between spaces, enacting their will on a reality that can never truly hope to behold them.
Powers and Stats
Tier: Varies, up to 1-A
Name: Varies, some remain entirely nameless
Origin: Cthulhu Mythos
Gender: Varies, inapplicable in almost all cases
Age: Varies, many are unbound by the concept of time
Classification: Absurdly ancient alien entities of immense power
Powers and Abilities: Immortality (Types 1, 4, and 10), Regeneration (Low-Godly, likely much higher for those whose true forms are undimensioned and formless), Non-Corporeal, Acausality, Reality Warping, Telepathy, Teleportation, Spatial Manipulation, Matter Manipulation, Mind Manipulation, Higher-Dimensional Manipulation, Energy Manipulation, Shapeshifting, Dream Manipulation
Attack Potency: Varies (Very few specific Great Old Ones demonstrate direct combat or destruction feats, and when they do, it is often not the full extent of their power, making many difficult to precisely judge), up to Outerverse level (Many Great Old Ones are completely undimensioned, walking freely between spaces as they interact with reality while nothing from reality can interact with them.)
Speed: Varies, the strongest are Irrelevant (They exist as completely dimensionless beings who can interact with existence as they please)
Lifting Strength: Varies, up to Irrelevant
Striking Strength: Varies, up to Outversal
Durability: Varies (Regeneration, Immortality, and transcending the concept of Death can make even the lesser Old Ones nigh-impossible to properly lay low), up to Outerverse level (Undimensioned and able to alter existence to their liking, while dimensioned beings are unable to even know their true form)
Range: At least Universal, as all Old Ones know everything going on in the universe at all times via their telepathy. Up to Outerversal for the dimensionless Old Ones
Standard Equipment: Varies, though many have cults, worshippers, or lesser races to do their bidding
Weaknesses: Certain lesser/dimensioned Great Old Ones must enter a deathlike slumber if certain conditions are not currently being met
Note: Many Great Old Ones have specific powers or ones well beyond those listed here. The Powers and Abilities section of this page simply lists those that all, or at least the vast majority, of the Old Ones possess.