It's been 4 months, all the veterans are gathered, I have the Chalice of Thunder, but I didn't get the Tear of Ashi (or do I need to find it)? The water elementals keep coming and coming, they completely overwhelmed me...
So, I understand that you can get to the dragon through the dungeon in the Necropolis lands?
The entrance to the dungeon is on Sandor's island, right opposite the island of the undead, and the exit is on the island of the undead, just a little further south (down) along the narrow strip of coastline, and you'll find the water dragon.