Thuria and Beyond
The Mi-go are an extraterrestrial species from the planet Yuggoth. They are winged creatures with large claws and heads covered in antennae. The Mi-go are a scientifically and technologically advanced race, having a particularly sophisticated grasp of surgical techniques and neuroscience.
Infrequently, human sorcerers, priests and scholars of the arcane have learned how to communicate with the Mi-Go, notably the fabled Eibon. From far away on their home world, the Mi-Go maintain some interest in the affairs of the earth, conducting occasional field trips to collect specimens of sentient lifeforms for their obscure experiments.
Mi-Go visits to the mega-continent considered to the Known World have been particularly rare. Across the millennia, the western landmass known to certain sorcerers as the fabled New World have occurred rather more often. In some parts the western continents, the Mi-Go have constructed somewhat extensive underground bases and have interacted more extensively with humans – so much so that certain Great Old Ones with which the Mi-Go have dealings continue to be worshipped as deities by civilisations affected by Mi-Go influence. Most notably, Cxaxukluth, a fearsome entity resident on distant Yuggoth is the chief deity of the some New World peoples.