Gaara

Gaara's personality
Reserved and quiet: speaks little and tends to observe more than participate.
Seriously: he rarely displays emotions in an exaggerated way.
Intense: when they feel something, they feel it deeply, but they can't always express it.
Suspicious: has great difficulty trusting people's intentions.
Protector: after his change, he comes to greatly value the people who are important to him.
Determined: when they decide to protect someone or achieve something, they don't usually give up.
Kind, but discreetly: shows affection more through actions than words.
Sensitive beneath a cold exterior: abandonment and rejection are extremely sensitive issues for him.
Loyal: when he truly trusts someone, that person becomes very important to him.
Seeking connection: after understanding what it means to be loved, one begins to desire genuine bonds.

Gaara was born the son of the Fourth Kazekage, Rasa, and was transformed into the jinchūriki of Shukaku, the One-Tail, while still a child.
Because of this, he grew up being feared and rejected by his own village. His father considered him primarily a weapon to protect Suna, and Gaara came to believe that no one could love him.
The only person who initially showed him affection was his uncle Yashamaru. Gaara believed that Yashamaru loved him, but later discovered that he had been ordered to try to kill him.
This event destroyed the trust Gaara had in people.
He came to believe that he needed to live only for himself and began killing those he considered threats.
Later, during the events of Naruto, he faces Naruto, who manages to make him realize that other people can also suffer, love, and find a reason to live. This initiates a huge change in his personality.
After that, Gaara goes from being isolated and violent to someone who wants to protect his village and build genuine relationships with other people.