Happy Mask Salesman
The Happy Mask Salesman is a recurring character in the Legend of Zelda series. He travels Hyrule and Termina collecting and selling masks. Some of his masks are very rare and powerful. Many of them can transform Link, and the most famous, the spirit-possessed Majora's Mask, can give anyone who wears it unbelievable power. The Mask Salesman's real name is unknown, and much of him is a total mystery. He has a very unpredictable personality, and will go from happy to extremely angry in seconds. He also seems to be able to do some magic, as is shown in Majora's Mask when he makes and organ appear, than plays the magic Song of Healing.
The Happy Mask Salesman first appears in Ocarina of Time, where he runs a simple mask shop in Castle Town. He asks Link to go out and sell his masks, and for every mask he sells he can get a new mask. This is an optional side quest called the Happy Mask side quest. If Link sells all four of the masks that the salesman wanted him too, Link gets to take the Mask of Truth, which allows him to read Gossip Stones.
The Mask Salesman is never seen outside of his shop in this game, and it is unknown where he goes after the seven years when Ganondorf takes over.