Tony Tony Chopper

Usopp is one of the protagonist from the One Piece game series. He is the doctor of the Straw Hat Pirates. When complimented, Chopper acts really sad and sometimes yells at the animal who complimented him to stop trying to make him happy. A running gag within the series is when other characters mistake him as a Japanese raccoon dog, and he angrily corrects them, pointing out his is a Reindeer.

The power of the Zoan-type Devil Fruit: the "Human-Human Fruit" provides him with the ability of human attributes, intelligence, and to transform into a full sized reindeer or a reindeer-human hybrid. A self-developed drug he calls Rumble Ball enables him to perform even more transformations.

History
Chopper is a reindeer who was treated as an outcast by both his fellow reindeer and humans who came to fear him, because his blue nose and he took on a human-reindeer hybrid appearance. He was rescued by Doctor Hiriluk who gave Chopper his name and made him his medical assistant.

After the terminally ill Hiriluk passed away, Chopper then became a pupil of another doctor named Kureha on Drum Island, learning all of her medical techniques and becoming a full-fledged doctor.

He meets them when the Straw Hats visited Drum Island in order to heal Nami. He later assisted the Straw Hats in defeating Wapol before joining them as the crew's doctor.