The sea is a terrible, powerful thing. How could anyone look upon it and not see the touch of the divine? The sea demands worship, placation, and so do the Harbour Gods. The sea can be tamed, and so can the Harbour Gods. This is the divine purpose of the Godtenders, to manifest and tame the divinity of the Sea of Sorrow, to appease them, and to unleash them upon the city's enemies before their numina corrupts the city into their image.
Through rituals passed down through generations, the Godtenders summon aspects of the sea, and then shackle them with prayers and nacreous chains. They enshrine them within The Break, appease and placate them, and when necessary, release them into the water to defend the city. Each god is an aspect of an unfathomable whole, each representing a fragmentary concept. Each god is unique, in both appearance and capability, reflective of the concept that spawned them and the faith of those that tend to them. Each shoal has their own god, their own traditions and methods of appeasal.
The district of Cartilay supports them. Though only the Godtenders themselves can manifest and tame their gods, the chains that bind them and the shrines that appease them are crafted there. The Godtenders never give the gods names, they refer to them only by titles (which are shared by generations of that god), to mitigate the risk of self-actualisation and rebellion as occurred with She-Breathes-Life.