Tony Tony Chopper is a reindeer who gained human intelligence, speech, and transformative abilities by consuming the Hito Hito no Mi (Human-Human Fruit). Born on Drum Island with a distinctive blue nose, he faced rejection from his herd even before eating the Devil Fruit. His hybrid appearance after consuming the fruit led humans to label him a monster, deepening his isolation. The eccentric Dr. Hiriluk rescued him, becoming his surrogate father and cultivating his passion for medicine and the symbolic meaning of the Jolly Roger. Driven by Hiriluk's terminal illness, Chopper sought a cure but inadvertently poisoned him with a toxic mushroom. After Hiriluk's self-sacrifice to defy the tyrannical King Wapol, Chopper apprenticed under Dr. Kureha, who taught him formal medical skills. His Devil Fruit powers grant three primary forms: Walk Point (full reindeer, enhancing speed and scent), Brain Point (small hybrid, optimizing intellect and observation), and Heavy Point (humanoid, maximizing strength). Chopper developed the Rumble Ball, a drug enabling temporary access to four additional forms: Jumping Point (enhanced agility), Arm Point (powerful forelimbs), Horn Point (sharpened antlers), and Guard Point (defensive fur). Consuming three Rumble Ball triggers Monster Point, an initially uncontrollable, life-draining berserk state. After two years of training, he mastered six forms without the drug and learned to control Monster Point with one pill, though extended use now causes a temporary "Baby Geezer" aging effect. He joined the Straw Hat Pirates as their doctor after they defended Drum Island from Wapol and invited him aboard, aiming to cure all diseases in honor of Hiriluk. Chopper displays naivete, emotional transparency, and a strong moral compass, particularly opposing unethical medical practices. Characters frequently mistake his Brain Point for a tanuki, provoking angry corrections. Post-timeskip, he embraces his "monster" identity to support his crew, showing increased confidence and medical expertise, such as creating antidotes for Caesar Clown's experiments on Punk Hazard and countering Queen's Ice Oni virus in Wano. Beyond the main series, he appears in the special *Dream Soccer King!* participating in a soccer match against the Villain All-Stars; his Heavy Point transformation accidentally destroys the ball during a penalty shootout before the Straw Hats win the tournament, later revealed as Luffy's dream. His design evolves post-timeskip: his fur lightens to gold, he wears a blue hat over his original pink one, and he adapts outfits to locales including samurai armor in Wano, a spacesuit in Egghead, and Viking attire in Elbaph. The Marines consistently undervalue his bounty, misidentifying him as a pet: 50 berries after Enies Lobby, 100 post-Dressrosa, and 1,000 after the Onigashima raid. He remains recognized as one of the Senior Officers of the Straw Hat Grand Fleet.