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Gorko is a Goron beset upon by Bokoblins when you first find him. He inhabits various areas of The Surface. A connoisseur of ancient culture, Gorko is interested in Skyloft.
heart piece
Gorko will give you a Heart Piece for showing him how to draw things on the Goddess Wall by the Sealed Temple entrance in Faron Woods. You can keep returning to this spot to show him how to draw Bomb, Arrows, Heart and Fairy symbols. After you draw the heart, he'll give you this Heart Piece.