Cthulhu.
A Demon Lord of mythical proportions. Many claim that once they laid eyes upon the horrific beast, they would lose all sense of reasoning. Their souls would be frozen, and their entire bodies would be rendered useless. And after seeing the enormous creature in person, I finally understood why.
Outer Demons were monsters that possessed unique sets of talents. They had enhanced bodies and increased magical capacity and often were monsters with supernatural powers beyond human capabilities.
And by that logic, a Demon Lord would be an extension of that. They were monstrosities that reigned over vast amounts of Outer Demons, utilising powers far beyond that of any regular living creature.
Alas, that logic was skewed.
When I look at Cthulhu now, I see a blob of natural energy. A deep ocean of magic power, and essence that took the form of a hideous creature. Demon Lords weren't enhanced Outer Demons… They were the spawn of the planet itself.