Gremlin Sunstar is a Gremlin who lives in Gremlin Villiage.
He hangs out by the Clock Cleaners V1 Projector Screen and asks Mickey to help with the Village Tower.
Once you repair the steam pipes in the center of the village, Sunstar teleports up to Mickey and thanks him. Gremlin Sunstar looks like the leader of Gremlin Village when Gus isn't around.