Huey, Dewey, and Louie

Huey (red), Dewey (blue), and Louie (green) are the three nephews of Donald Duck and relatives of Scrooge McDuck. In Kingdom Hearts, they work in the item shop in the First District of Traverse Town. Here, the three take turns selling items. In Kingdom Hearts II, they run an item shop, a weapon shop and an accessory shop in Hollow Bastion. In both endings, they are all seen going back to Disney Castle.

Huey
''One of Donald's three nephews. Huey is the leader, and he keeps playful Dewey and laid-back Louie in line. You can spot Huey by his trademark red cap.''

Huey began tormenting his Uncle Donald in "Donald's Nephews" (1938).

Dewey
''One of Donald's nephews. Always wears a blue cap. Cheerful and easygoing. He works with his brothers in a shop in Traverse Town.''

Dewey began tormenting his Uncle Donald in "Donald's Nephews" (1938).

Louie
''One of Donald's three nephews. Works with his brothers in a shop in Traverse Town. Gentle and carefree, but notices a lot of things others miss. To find him, look for a green cap.''

Louie began tormenting his Uncle Donald in "Donald's Nephews" (1938).

Huey
Donald's Nephews (1938)

''One of Donald's three nephews, Huey is the leader of the bunch. He keeps Dewey's plans in line and makes sure Louie doesn't fall behind while they help out with Uncle Scrooge's ice cream business. You can spot him by his trademark red cap.''

The last time we saw Huey, he was working in Traverse Town, saving up for an expedition.

Dewey
Donald's Nephews (1938)

''One of Donald's three nephews who's helping out with Uncle Scrooge's ice cream business. Dewey always wears a blue cap. He's smart and cheerful and likes to come up with plans to have fun.''

The last time we saw Dewey, he was working in Traverse Town, saving up for an expedition.

Louie
Donald's Nephews (1938)

''One of Donald's three nephews helping out with Uncle Scrooge's ice cream business. Louie is gentle and carefree, but notices a lot of things others miss. To find him, look for his green cap.''

The last time we saw Louie, he was working in Traverse Town, saving up for an expedition.

Shops
In Kingdom Hearts, Huey, Dewey and Louie take turns being the shop barter in the Item Shop in Traverse Town. In Kingdom Hearts II, Huey is in charge of the Accessory Shop, Dewey is in charge of the Items Shop and Louie is in charge of the Weapons Shop in Hollow Bastion/Radiant Garden.

Kingdom Hearts Birth by Sleep
The trio appears in Disney Town participating in the world's mini games.

Kingdom Hearts
Judging by conversations with the three in Traverse Town in the item shop, one can clarify that the three brothers went off to seek their fortune. They tell Donald that they wished to make money so they went off to start their shop. Though one must wonder how they got off their world.

Kingdom Hearts II
They also appear selling stuff in their shops but this time in Hollow Bastion and each of them have their own shops.

Kingdom Hearts coded
The three were shown in Kingdom Hearts coded, during Sora's adventure in Data Traverse Town in Episode 2. Data Cid was looking for them when Sora shows up he asks Sora to look for the triplets.

Family
Huey, Dewey, and Louie are related to Donald Duck, Scrooge McDuck, and they address Daisy Duck as their aunt.

Trivia

 * Strangely, it's not ever shown how Huey, Duey, and Louie ever got to Traverse Town if Disney Castle wasn't destroyed. Plus, it's unknown why they wouldn't be at Disney Castle in Kingdom Hearts II, but instead at Hollow Bastion.
 * Despite being depicted as kids in Kingdom Hearts, the trio still exist ten years in the past (during the events of Kingdom Hearts Birth by Sleep), living in Disney Town. This suggests that they may be older than they look.

Riri, Fifi et Loulou