I met a really weird guy on the island due
That area is
The Three-Eye Reef is a location from The Wind Waker. Three-Eye Reef is the third of the Eye Reefs and is located three squares south of the Forsaken Fortress. It has a square outer shape and three stone pillars in the middle, giving it the shape of something with three eyes, or the 'three' side of a die. When Link destroys all of the Warships and cannons protecting this island, a treasure chest will appear holding Treasure Chart #32.
Piece of Heart
One of the items sold at Zunari's night auctions at Windfall Island are Treasure Maps. If Link wins the auction and wins a Treasure Chart, he can pull up a Piece of Heart from the bottom of the ocean at this island.