I am working on Sunken City right now. I defeated all the levels of the tower before the final tower. I can't find whatever I am looking for in that tower and I can't go any further up the tower. What am I missing? I'm stumped.
I'm guessing you're on the quest Under Lock and Key, as that's where the tower is. It's the third major part of Sunken City out of four. Norten's tower is in the top center of the map. You go past its culdesac when you go talk to Marla Stinger, and then have to backtrack. It's near the living scarecrows.
If you're past that and looking for Grubb, he's at the far right corner of the map.