The master of the Hounds of Tindalos, Mh'ithrha is the mightiest member of that strange species. Although invisible to the human eye, it's physical form is said to be that of a gargantuan wolf, somewhat resembling the beast Fenrir from Norse mythology.
Mh'ithrha has been engaged in a war with Yog-Sothoth for all of eternity; stories of this conflict are the stuff of legend in the Cthulhu universe, and the fact that it has not been annihilated by such a being gives a hint to the true extent of Mh'ithrha's power.
- Mh'ithrha made its only appearance in Bruce Ballon's Call of Cthulhu Roleplaying Game splatbook Unseen Masters: Modern Struggles Against Hidden Powers (2001).
- Mh'ithrha was inspired by Fenrir, the great wolf of Norse mythology.