In the Titus Crow stories by Brian Lumley, one of the sons of Cthulhu. He is, apparently, 'interred in crypts (Why does he need multiple crypts? Eh well. He's one of the Cthulhi, anything is possible) beneath a primal mountain, now lost in depths of ocean at the southern edge of the southeastern Pacific Plateau, about a thousand miles south of Easter Island'.

Which would put him at, mmm, very roughly, S. 40, W. 110, if anyone fancies Cosmic Calamari for dinner.