Where exactly is Serpents Hold?
There is a small island marked on the map southeast of Trinsic, at 75 58′ south, 7 1′ east. Note that a bug with the sextant is likely to result in it saying North instead of South. The island is also distinguished by being only sand with a ruined wall on it, and being guarded by a hostile ghost. Standing on the island, look southwest into the water to see a ruined tower below the surface. The entrance to Serpent’s Hold is a hole in the former roof of the tower. Once in the passage, you need to swim down it and get through the force field quickly before you run out of breath. A blue potion or the Mana Breath spell helps here. The force field only blocks the passage of air and water, not the Avatar.