Ithaqua (the Wind-Walker or the Wendigo) is a fictional character in the Cthulhu Mythos of H. P. Lovecraft. The titular creature debuted in August Derleth's short story "Ithaqua", which was based on Algernon Blackwood's tale "The Wendigo". It controls snow, ice and cold, and can walk through the sky as easily as it walks on earth. 
Ithaqua in the mythos
Ithaqua is one of the Great Old Ones and appears as a horrifying giant with a roughly human shape and glowing red eyes. He has been reported from as far north as the Arctic to the Sub-Arctic, where Native Americans first encountered him. He is believed to prowl the Arctic waste, hunting down unwary travelers and slaying them gruesomely, and is said to have inspired the Native American legend of the Wendigo and possibly the Yeti.
Ithaqua's cult is small, but he is greatly feared in the far north. Fearful denizens of Siberia and Alaska often leave sacrifices for Ithaqua—not as worship but as appeasement. Those who join his cult will gain the ability to be completely unaffected by cold. He often uses Shantaks, a dragon-like "lesser race", as servitors. A race of subhuman cannibals, the Gnophkehs, also worshiped him, along with Rhan-Tegoth and Aphoom-Zhah.
Ithaqua figures prominently in Brian Lumley's Lovecraft-based Titus Crow series, ruling the ice-world of Borea. In Lumley's works, Ithaqua periodically treads the winds of space between Earth and Borea, bringing helpless victims back to Borea to worship him among its snowy wastes. He frequently attempts to reproduce with humanoid females, hoping to create offspring which can surpass his own limitations, imposed by the Elder Gods, and so help free the rest of the Great Old Ones. It is suggested that Ithaqua has the ulterior motive of desiring offspring to assuage his bitter loneliness, as he is the only one of his kind. None of his surviving offspring to date has accommodated him, all turning against him at some point.
Anders Fager's "The Wish of the Broken Man" describes how 18th-century Scandinavian Saami worship "Ittakka" and calls up on him to create blizzards. It also fingers Ittakka/Ithaqua as responsible for the 1718 Carolean Death March.
- Derleth was inspired by Blackwood's tale (who himself based the Wendigo on a creature from Native American Indian legend), but gave the creature a Lovecraftian name. (Price, "Ghost Riders in the Sky", "Who Has Seen the Wind?", The Ithaqua Cycle, pg. xi.)
- "Crazy Ivan's Timeline of Werewolf and Therianthrope Fiction"
- "A Hyperborean Glossary by Laurence J. Cornford"
- "Anders Fager (2011). Collected Swedish Cults. Stockholm, Sweden: Wahlström & Wistrand. ISBN 9789146220961."
- Blackwood, Algernon (1998) . ""The Wendigo"". In Robert M. Price (ed.). The Ithaqua Cycle (1st ed. ed.). Oakland, CA: Chaosium. ISBN 1-56882-124-7.
- Derleth, August (1998) . "Ithaqua". In Robert M. Price (ed.). The Ithaqua Cycle (1st ed. ed.). Oakland, CA: Chaosium. ISBN 1-56882-124-7.
- Lumley, Brian (1993) . "Born of the Winds". Fruiting Bodies and Other Fungi. Tor. ISBN 0-14-017302-1.
- Price, Robert M. (1998). "Introduction: Ghost Riders in the Sky". In Robert M. Price (ed.). The Ithaqua Cycle: The Wind-Walker of the Icy Wastes (1st ed. ed.). Oakland, CA: Chaosium. ISBN 1-56882-124-7.