Let's expand where we have the most interest. "Ebb" of Aqua. I like the idea of a source of this disaster. Possibly our 'totes not a cult' Nocnitsa are stoking the god-like entity in control of the seas into damning this town who's political body had denied the recognition of Nocnitsa as a religious entity/political power/etc. The Governor/Mayor/Leader-Type Body/Collective Parliament/Clove of Garlic/'The Man' calls for researchers, adventurers, guardsmen, and the like to help prevent or to an extent suppress the deathly tides. I love the idea of this city struggling to figure out it's doom, yet thriving from those who come to help solve the problem in spite of the circumstances. Nocnitsa could have agents spread throughout exploring teams or city-side support groups to help cripple the efforts. Their goal isn't to totally annihilate "Ebb", but rather control it and expand their domain to allow their 'gifts' to thrive outside Spinel.

I could have the wrong idea of Nocnitsa, but I kinda like the passive-aggressive style of sabotage in attempt to expand their proverbial 'territory.'