Herb is filthy, stinkin' rich, and he is also a collector of Figurines. He tells Link that if he ever finds a complete set of figurines, he should let him know. If Link has acquired all 136 Figurines, he can speak with Herb outside of Mama's Cafe and Herb will give Link a key to his house. Herb's house is located immediately to the north of Mama's Cafe. Inside, Link will find a Piece of Heart, three treasure chests that each contain 200 Rupees, and a Phonograph that allows Link to access the Sound Test.
Link is able to fuse Green Kinstones at various points in the game with Herb. As it is a Green Kinstone fusion, it is not set to a specific treasure chest, but instead, one of the many possible treasure chests. There is one random Red Kinstone within the game that opens up a location in the Hyrule Castle Garden leading to a Piece of Heart, as well as a random Blue Kinstone that opens up a tree in North Hyrule Field leading to a Fairy Fountain. Herb is one of the many characters in which Link can make these Kinstone fusions with.