When I didn't see anything else, it's not exactly terrible thinking to imagine there's some way to get onto the clearly visible staircase. I examined it from all angles and there was a place on the main staircase between the gap that the player could cross. Theoretically, if I made it to the base of the staircase, I could climb it. I tried everything. Scaling cliffsides, scaling coral, falling from heights, avoiding level 70 King Piranhas, swimming everywhere for an entrance, nothing. There was no good direction on where I was supposed to go in this area beyond this town and it didn't help that a boulder obscured the actual staircase I had to climb. This was the lowpoint of my adventure and I'm just going to look up a walkthrough if it gets this bad again.