Grog

Grog is a character who first appears in Ocarina of Time, where he can be found in Kakariko Village when Link is a child. He sits underneath the tree near the village entrance at night. He is Mutoh's son, Anju's brother and a bit grumpy (or perhaps angsty, given his punk rock look). He appears to have some kind of relationship with the potion shop lady.

Ocarina of Time
As a child, Grog can be found sitting under the tree near the entrance to Kakariko Village.

Later when Link is an adult, Grog is part of the Biggoron Sword sidequest. In Kakariko Village, if you talk to Anju, the cucco lady, she will give you a Pocket Cucco after you hatch it overnight, go to a lady's house and awake the sleeping man, Talon with it. Show Anju an she will give you a blue cucco named Cojiro, whom she said was her brothers cucco and would only crow for him. Link will find Grog in the Lost Woods sitting beside a tree stump where the Skull Kid would play his flute. Show him the cucco, he will give you an Odd Mushroom which Link must give the old hag who owns the medicine shop in Kakariko. She in turn will give you an Odd Potion to give to Grog. Although when you returns to the forest to give Grog the medicine, Fado is there. She explains that due to the fabled curse of the woods, Grog is gone and has become a Stalfos.

Majora's Mask
In Majora's Mask he has a completely different role. He is the owner of the Cucco shack and loves his cuccos, but when he hears the rumor that the moon will fall on Termina in three days, he is filled with sorrow as he understands he won't see his cuccos develop into roosters. By playing the Bremen Mask song, you can help him to see his cuccos grow up.

Trivia

 * In common day usage, grog is slang for an alcoholic drink, originally composed rum and water, known for being a popular beverage among pirates.