Great Old One image
Cthaeghya is a Great Old One who appears in the H.P. Lovecraft-inspired Cthulhu Mythos.


Whilst mortal knowledge of Cthaeghya is slim, it has been gleaned that this entity is both the half-sister of Great Cthulhu and his mate, birthing the Star-Spawn of Cthulhu to her sibling. From the appearance of both her half-brother and their offspring, it could be assumed that she is somewhat octopoid in her appearance. 

Cthaeghya's current whereabouts are unknown, although the fact that both her mate and their children waged war against the Elder Things on Earth in the far distant past may mean that she lies dormant somewhere on our planet.


  • October Surprise (2006), by Kevin L. O'Brien.