"I wouldn't know to contact them directly, but they make their home in the sewers that flow into the river and sea; the most convenient entry to which is along Harbour Street. The one or two that live down their are bound to be curious of any folk entering their domain, and they'll no doubt seek you out." Nicodemus moves to desk and pulls open a drawer and rummages through it. He retrieves a plain copper ring and hands it over. "This is enchanted to act as a tinderbox. Feel free to trade it for information or anything else you might want from the sea hags. You might also try enticing them with news of current events in the city, like the cult and such. They enjoy collecting magical artifacts and stories of magical folk and creatures. Of course it goes without saying that you shouldn't trust them."
Nicodemus considers Rosa's second request for a moment. He shrugs and pulls a small leather-bound grimoire from his robes and begins leafing through it's weathered pages. He stops on a page and traces his finger across the page, his mouth moving soundlessly. "I suppose I could try a simple locating spell... here we are. If you could hand me a single strand of hair, thank you."
Nicodemus holds the strand of midnight black hair in his hand and traces symbols in the air with it. The strand leaves slight shimmering distortions, like heat waves, as it moves. Nicodemus clears his throat and utters the words: "Lleolwch y creadur hwn, pwyntiwch fi ato!" A faint smell of ozone permeates the room. Nicodemus slowly turns about in place with his arm extended. He furrows his brow, and completes another turn. He very slowly completes a third, and then lets his arm fall to his side. The smell quickly fades, and Nicodemus shrugs.
"Hmm. Either the night hag isn't in the city anymore, or more likely, is not in her true form. That's the trouble with blasted shapeshifters; the simpler divination magics only work to locate them in their natural state. I'm afraid I'd need to conduct a more powerful ritual to seek her out. If you are intent on it, then I'll need you to fetch me one of the following for it: A crystal ball, or a pure silver mirror. A large volume of holy water might work as well, but I think that may be even more difficult to acquire. But I leave that up to you."