Ithaqua (also called the Wind-Walker or the Wendigo) is one of the Great Old Ones from the fiction of H.P. Lovecraft.

According the Lovecraft's Cthulhu Mythos, Ithaqua is reported from the Arctic to the Sub-Arctic, where Native Americans encountered him. He is known to stalk the wastes, tracking down hapless travelers and carrying them off. Such unfortunates are found weeks or months later, buried partway as if dropped from a height, frozen solid in positions of great agony, and missing random body parts.

Ithaqua has a minimal cult, though many fear him in the far north. The inhabitants of Siberia and Alaska may leave sacrifices to keep the Wendigo from haunting their camps, but organized worship seems to be rare.

August Derleth based Ithaqua almost wholly on the superior tale "The Wendigo" by Algernon Blackwood. The Wendigo is an actual Native American legend, although the North American tribes that believed in the legend ranged considerably farther south than the Arctic wastes Ithaqua is said to roam. The Wendigo has been utilized in many works of fiction, from Stephen King's Pet Semetary to The Wendigo by Theodore Roosevelt to its portrayal as a vengeful forest spirit in the movie Wendigo. Ithaqua features prominently in Brian Lumley's Lovecraft-based Titus Crow series, ruling the ice-world Borea. In Lumley's works, Ithaqua periodically walks the winds of space between Earth and Borea, bringing helpless victims back to Borea to worship him among its snowy wastes.

(Information taken from the Chaosium Call of Cthulhu Role-Playing Game)