This port is one of the notorious places in all of the Known World.
It is home to thieves, assassins, spies, and other undesirables (as well as a good amount of monstrous beings) and is ruled by the Thieves’ Guild. It is rumoured that the head of the Thieves’ Guild is some sort of aberration, but this has never been confirmed.
It is not-a-well-kept secret that the Guild sponsors pirates to waylay ships off the coast and then brings that wealth back to Grimport’s coffers.
Grimport sits in a walled crater formed when a Starstone crashed into the ground. The whole crater, and thus the city, sits in a dead magic zone. No magic will work with the city.