The path of Humakt is as sharp and severe as the edge of a sword. Humakt has no associated cults – you need to worship him directly to gain his magic.
Humakt is friendly only to Orlanth, Ty Kora Tek, Telmor and Yinkin. That’s pretty much it. He’s neutral to most other deities except for most Chaos entities, most Lunar deities, and Zorak Zoran, all of which are hostile. He has few enemies – only Vivamort, Gark, the Red Goddess and the Red Emperor.
And Honor is so central to the cult. Violate your geas and you are no longer worthy of carrying a sword (and suffer the cult’s curse). Violate honor and you run the risk of the same.
As an aside, Claudia and I recently watched Blue Eye Samurai and we both agree that Mizu makes a great Sword of Humakt.
Why does Humakt go from hostile to enemy with the Red Goddess and Emperor? Although Humakt is neutral towards Yanafal Tarnils (the cults can certainly cooperate), he is the enemy of the Red Goddess and the Red Emperor.
Why is Humakt friendly to Telmor? Telmor is a Death god and Humakt is a popular cult among the Telmori. I suspect this friendship is from the Telmori themselves.