Keeper of the Shallows is a Spout Boss that can occasionally be found on Isla Tormenta, in Forsaken Shallows. This boss can be difficult even for high-level pirates, so its recommend you bring a crew to help fight this boss.
It appears at Levels 47-52.
Keeper of the Shallows was not originally in Pirates of the Caribbean Online. It was added to The Legend of Pirates Online.