Chopper is the fifth member (※) of Monkey D. Luffy’s crew and the Straw Hat Pirates’ ship’s doctor.
He is a “human-reindeer” who ate the Zoan-type Devil Fruit, the “Hito Hito no Mi,” making him the second capable crew member after Luffy.
Born on Drum Island, the winter island of the Grand Line, he is also the sole physician in his country and a disciple of Dr. Kureha. Despite being a reindeer, he possesses advanced medical skills and knowledge, and is highly skilled in concocting medicines—such as the Rumble Ball, which enhances his transformation abilities.
Originally, together with his mentor Dr. Kureha, Chopper made his home in Drum Castle, the ruins of the former Drum Kingdom. He would descend to the foothills, barge into the homes of seriously ill patients, treat them without hesitation, and then seize exorbitant sums of money—often taking their household possessions and daily necessities.
When Luffy and his crew landed on the Primitive Island to treat Nami, who had contracted an ancient illness, Chopper treated them despite the blizzard, having braved the harsh conditions all the way to Drum Castle. Having endured years of unjust persecution from most people he’d encountered, Chopper initially remained wary of Luffy and his companions upon regaining consciousness. However, during the battle against the former Drum Kingdom’s king, Wapol, Chopper came to recognize them as allies and rediscovered the principles taught to him by his former mentor, Dr. Hiruluk. Moved by Luffy’s earnest invitation, Chopper joined the crew.
He is a bipedal reindeer wearing a white hat marked with a red X, a blue backpack, and maroon shorts. His horns and ears protrude from the hat; the horns have a distinctive shape resembling human hands. His left horn was broken when he was found by Hiruluk, so it is now secured with a metal ring and screws.
At first, Chopper’s face resembled that of a reindeer, but as the story progressed, his design became increasingly stylized, eventually evolving into the adorable visage seen in the main artwork.
Incidentally, in the anime, cute sound effects like “pochopochi” accompany Chopper’s walking.
In his human–beast form, he’s often mistaken for a tanuki; in beast form, just a deer; and in human form, even a gorilla or Bigfoot—no one has ever properly recognized him as a reindeer.
Public perception and treatment of Chopper are far from that of a ship’s doctor—he’s regarded more as a rare pet kept by the crew, and little is known about his true nature. (To be fair, this very obscurity has allowed him to quietly play unexpected roles, frequently rescuing the crew from peril.)
Whenever he goes out, he always carries a blue backpack filled with medicines and essential first-aid supplies.
Two years later, he wears a light-blue, helmet-like cap over his original hat and dons a yellow-striped shirt.
Despite his cute appearance, Chopper refers to himself as “ore.” Though his speech is rough, his personality matches his looks: serious, kind, gentle, timid, and prone to tears.
He almost always addresses others as “you” or respectfully as “Doctor,” never calling them “you.”
At the beginning of his time with the crew, Chopper was quite shy, but through numerous adventures, he gradually grew more confident. In particular, he used to be extremely shy around strangers, habitually hiding behind objects whenever someone unfamiliar approached.
Yet when he does hide, rather than concealing his body while exposing only his head, he often hides his head and reveals his body instead. And when he sees comrades or ordinary people injured, he’ll crack jokes like, “Where’s the doctor?!” followed by, “It’s me!!” — showing a strong streak of natural comedic flair.
Moreover, Chopper is even more easily deceived than Luffy, and still hasn’t figured out the true identity of Sogeking.