Yan of the Hidden Village (隠れ里のヤン, Kakure Sato no Yan) is an additional event in Tomba! 2: The Evil Swine Return.
To clear this event, you must go to the west part of Circus Village and go through the laughing door. Inside, you'll find Yan hiding behind a camouflaged blanket. Go up and talk to him to clear the event.