Tony Tony Chopper/Personality and Relationships

Personality
Chopper is naïve and extremely timid, often acting like a child because he does not know any better. Like Luffy, he is easily impressed at things like beams, cannons, and hidden abilities. He is a coward at times like Usopp and Nami, although his cowardice can be attributed to his childishness and overall lack of trust in his own fighting skills (a contrast to Nami's self-survival based cowardice and Usopp's insecurity based cowardice). Chopper is more or less on a journey to define himself, seeing almost anyone on his team as a role model and in some cases, imitate their behavior, especially Usopp.

He is an upright friend and companion who will try anything to overcome a task given by his team. He still has a feeling of distrust for humans from his youth, and will often outright insult and claim that compliments do not make him happy to a human who compliments him while obviously being happy about it (he starts to do the "Dirty Old Man" dance which was a bit by famous Japanese comedian Ken Shimura, which became a running gag).

Chopper seems to be very forgiving of those close to him, for when Usopp wanted to rejoin the crew at the end of the Enies Lobby Arc, he called out to Luffy and Zoro, although they were ignoring him completely. He would rather run and hide than fight, but becomes more courageous when others are there to support him.

His dream is to carry out his deceased mentor, Hiluluk's belief that there is no incurable disease, and to become a doctor that can cure any illness. To this end, his childish nature vanishes whenever his medical skills are required; he does not hesitate in the least in any actions regarding the well-being of his patients.

Chopper also has the strong belief that a doctor is supposed to help save people, and becomes angered when somebody treats life without the proper respect. This was why he was greatly angered at his former hero, Dr. Hogback, when the man treated the patients' and Zombies' lives, and deaths, so callously. He was also enraged at Caesar Clown, for kidnapping and experimenting on children, and making them addicted to drugs.

Another one of Chopper's habits is his reverse cartoon peek, where he stands behind a wall or a doorway and peeks at people, trying not to be seen by them. Unfortunately he is not hiding his body behind the wall, as a result his body is visible and only one half of his face is hidden.

A running gag is that Chopper will believe just about anything he hears, making him easy prey for Usopp's stories. He also believed Nami when she lied to Lola about being a man, even though the truth was very obvious. In fact, until Jinbe stated otherwise, he thought that the captain's duty was not to listen to anyone.

He also tends to panic quickly, and subsequently let some crucial facts slip his mind. One example is when there is someone who is injured, he often panics and screams "Call a doctor!!". It is not until he figures out that he is the doctor that he starts to tend to the injured person. Another one is when he (and Brook) jumps into the water without hesitating to save Luffy from drowning, only to drown with him (since the Devil Fruit that he ate makes it impossible for him to swim). He, together with Brook and Luffy, ends up being saved by the other members of the crew.

After the timeskip, Chopper seems to have grown more confident, much like Usopp. He no longer strives to be looked at as a human, now only wanting to "be a monster that can help Luffy" as he put it. He even has grown mature enough to smack his nakama, mostly Zoro and Luffy, when they try to do something stupid or extreme. He also seems to have outgrown the habits mentioned above.

Crew
Within the group, Chopper often fools around with Usopp and Luffy for laughs and is also a thankful listener to Usopp's lies, most of which he really believes, at least for a short time. Frequently, Chopper is one of the first to join in with Luffy's antics, as well as watching in glee for some of Usopp's stunts.

Chopper also seems to have a close relationship with Zoro, whom Chopper near idol worships because he is "so cool". One of his favorite things to do is to ride on Zoro's shoulders when they are traveling and often runs to him when he is scared. Zoro also seems more protective of Chopper than anyone else. It is seen that Zoro is the one to save him when he comically falls into any form of water when trying to escape Nami's wild mood swings (while Sanji has saved Luffy frequently in comparison), though Chopper still gets annoyed with Zoro whenever he takes off bandages from injuries he sustained from battles.

Sanji originally wanted to cook Chopper (along with Luffy who wanted to eat him raw) and jokingly wants him to join as "emergency food supply" later in the Drum Island Arc. Throughout the series, Sanji continues to refer to him as "the emergency food supply" to tease him but considers him a friend. Chopper was one of the first people to realise how life threatening Sanji's nose bleeds were, even begging the fishmen for blood donations.

He shares a taste for reading with Robin who called him "Doctor-San" when she first joins the crew, which made him dance in joy. They also seem to have a genuine sense of respect for each other, possibly due to their pursuits in knowledge; ironically, he was originally rather intimidated of Robin upon finding out that she specializes in assassinations, fearing that she will one day assassinate him once his guard has been let down, but at the same time, was amused when she first displayed her Devil Fruit powers to entertain both him and Luffy, and eventually opened up to her. His fondness towards Robin is what compelled Chopper to use his Monster Point Form against Kumadori during his battle in the Judiciary Tower. In return she treats Chopper not only an equal in terms of intellect but also with a motherly nature as she got him out of the clutches of Foxy's right hand woman.

He is amazed by Franky's inventions and shows a great respect for him. He also admires Franky's robot body, especially after the timeskip when Usopp warned him that too much excitement would kill him.

When Chopper first met Brook, he was terrified of him because he was a walking, and talking skeleton. But after hearing the story about Brook and Laboon, Chopper cried and stated he was not afraid of skeletons anymore. They get along very well when he joins the crew.

Notably, Chopper originally was not hired to be the ship's doctor by Luffy, but just for being a "talking transforming reindeer monster." The other boys of the crew have often mentored Chopper on what it means to be a real man; He is the youngest crewman, not originally human, and has had a relatively sheltered life. Within his combat relationships, he has at least three canon team attacks, and as a homage to his personality (which can be easily influenced), each of the attacks are named with half of the other crew member's name and half of his name. All of the examples feature the fellow crew member's name first in the name then his own such as "Hissatsu Uso-Cho Hammer Suisei" where Usopp's name is the first mentioned.

Drum Island
Back on Drum Island, the people have come to accept his help in defeating Wapol, even though originally they were afraid of him.

Dalton
Dalton also has a sound view of Chopper, whom he views with the highest respect having saved the kingdom of Drum and was the one who saved his life six years ago by stopping an angry Chopper from fighting a hopeless battle against Wapol and his army to avenge Hiluluk's death, having recognized what he was trying to do. He keeps an eye out for Dr. Kureha's "son" and was the first to tell her when Chopper gained a bounty.

Torino Kingdom Citizens
After being "sent" to the Torino Kingdom, Chopper was very distressed as he was treated as a plaything by the birds and hounded by the natives as food. However, after Chopper managed to resolve the conflict between the natives and the birds, he was treated almost like a hero. After receiving Luffy's message he returned and the natives were glad to share their knowledge of herbs, medicines, and plants with Chopper, especially after he helped solve their conflict. The giant birds of Torino Kingdom were also happy to fly Chopper to the Grand Line whenever he wanted to.

Wapol
One of Chopper's major enemies is Wapol, the spoiled king who insulted the death of Chopper's surrogate father, Dr. Hiluluk, among other things. With Luffy’s coming, Chopper not only managed to get revenge for his father but also with Luffy’s aid they managed to prevent Hiluluk’s flag from being burnt.

Marines
He is wanted by the Marines, albeit with an extremely low bounty of only fifty beli due to being mistaken as a pet, and with only one of his transformations noted in the bounty poster.

Hogback
Chopper initially idolized Dr. Hogback solely based on his reputation as a doctor of legendary skills, and outright and angrily stood up for him when Nami and Usopp spoke negatively about him based on the suspicious circumstances, despite barely knowing the man personally. However, after learning of his disregard for human life and that he uses his medical expertise only for fame and wealth while considering his patients as annoyances (as opposed to Chopper's philosophy of a doctor must cure any patient regardless of reward), as well as coming into conflict with him and the rest of Gekko Moriah's forces, he declared that he no longer considers him a doctor, and even tried to smash his head in.

Caesar Clown
Despite not having had a personal encounter with Ceasar Clown as of yet, Chopper has quickly grown to despise the mad scientist after finding out the cruel experiments he conducted on the children he kidnapped, similar in a way to Dr. Hogback.

The Herd
Chopper's biological family is a herd of reindeer, who abandoned him for being different. Initially estranged for being born with his blue nose, he is further abandoned after eating the Hito Hito no Mi, which gave him two "unreindeer-like" humanoid forms. He eventually found his path intertwined with them again during his days with Hiluluk when he was beaten up by them (where his left antler was broken). However, he was able to pass through them despite this and achieve his goal at the time.

Hiluluk
Hiluluk was Chopper's mentor who took him in and became his "father".They had a close relationship with each other, and had formed a deep bond despite their almost constant arguing with each other and Chopper had a hard time when he was informed of the disease Hiluluk is suffering from. He found Chopper one day while traveling home in a blizzard. At first Chopper tried to knock him away, but Hiluluk earned his trust by stripping naked in the cold, showing that he did not have any weapons or intention of hurting Chopper.

From then on, the two slowly formed a sort of father/son relationship, traveling (and in a way terrorizing) the island trying to cure patients and generally resulting in them having to literally run for their lives from angry patients or their associates. Despite his time spent with the superior Doctor Kureha, Chopper refers to Hiluluk as "the greatest doctor in the world." Hiluluk also gave Chopper his name, claiming his antlers looked like they could chop down trees.

Kureha
When she realizes that Hiluluk is dying, she agrees (reluctantly) to his last requests: to make his life's work come to fruition and to train Tony Tony Chopper in medicine. During the time since Hiluluk's death, she trains Chopper in medicine, claiming she taught Chopper "everything she knew", and was fairly impressed by the young reindeer's skill. She only once complimented Choppers skill in a filler episode, after Chopper cured her of a life threatening illness without any of Kureha's medical advice. Though neither family nor claiming to have adopted him, Dr. Kureha is his mentor. While she often hides her feelings towards him she considers him to be like her son. She is very happy to know he is currently doing well.