Gotta dodge the laser beams!
In one of the deeper vaults on the island I found an army of dwemer spheres busy at work and proof of the Kraken's origin. I mean who else would construct a giant mecha right? After destroying Mazinger Z, I cleared as many more enemies as I could but then had to return, leaving the rest of Summerset Isle's conquest in the capable hands of the sisters and their soldiers.
This is because the mod is unfinished, and I ran into the speedforce.
Upon returning to Skyrim, Brutus told me that during his incarceration he learned of a secret Thalmor under the ocean. The best way there would be via rowboat, and would need to be a solo mission as to keep it low key. Because I like surprising people. This was fine since Braga Clearwater basically "graduated" and was now a competent adventurer. I gave her a big hug and sent her on her way, then found myself a boat.
Well, that's specific...
At the coordinates Brutus gave I found an unguarded tiny island and a fisherman's shack. Under the bed was a trap door that led to a huge cave system though, guarded by a ghost and his ghost dog. Yeeeah ok. After splattering their ectoplasm all over the walls I found stairs leading even deeper.