A great Ancient from the game "Eternal Darkness" for the Nintendo Gamecube.
Ulyaoth, the Master of the Planes, might just be the most unique out of all three ancients. He controls all blue magick and creatures. He is extremely intelligent, and has a voice that is cool, precise, and easy to listen to. Don't let this fool you, though; Ulyaoth is just as unholy as the other ancients.
He is kind of like a giant, blue jellyfish type of creature, with five or six round, enchanted projectiles circling the top of his body. His many tentacles have the ability to create portals to either other places or even time streams, thus giving him an unpredictable attack, in which he uses these portals to separate body parts in other dimentions.
With his mastery of magick, Ulyaoth can crush the power of Chattur'gha, but since he is not knowlegable of the effects of madness, he would surely fall to the insanity of Xel'lotath.
If you really listen to him, you can learn a thing or two from Ulyaoth. Although he is gone like the other Ancients, there are still rumors of stray portals roaming the universe...
ULYAOTH - "The Universe is a yawning chasm, filled with emptiness and the purile meanderings of sentience."