The Tethyos Houses are the only mentioned great Houses of the largos. Little is known of the Tethyos Houses; they hold their members to the Tethyos Compact, also called the Concordat of the Tethyos Houses.
Trophies of good kills are presented to the great Houses in the name of the hunter who made them. The greater the challenge in a successful hunt, the higher societal status a largos holds. The largos invoke the name of the Tethyos Houses when they honor an oath or greet an ally.
- In Greek mythology, Tethys was a Titan sea goddess, who embodied all the world's waters.
- ^ Wet Work
- Sayeh al' Rajihd: Impressive. I will present this trophy to the great Houses in your names. You have earned the right of introduction: I am Sayeh al'Rajihd.
- ^ Temple of the Forgotten God
- Sayeh al' Rajihd: In the name of the Concordat of the Tethyos Houses, I greet you, ally of my ally.
- ^ The Source of Orr
- Sayeh al' Rajihd: I have long owed Trahearne. By the Tethyos Houses and the shadowed Scions, I will pay that debt in full today.