Lol. Just kidding.

Go up the stairs behind the cannon (or take the slope to the right of the stairs).

Follow the path around to the southwest and continue along it.

Take the first branched path you come to on your left and follow it south.

Again, take the first branch you come to on your left. It will lead you to the sea wall path. 

But the troll is gone.

Maybe that tree within a circle of stone to the east knows where it went. Approach it.

The tree speaks to you…