The character I will be analayzing is Train Heartnet from the manga series Black Cat.
Train Heartnet (aka Black Cat) once was an assasin for a group of assassin sfor a criminal organization, Chronos, called the Chronos Numbers (Heartnet was number thriteen. When he meets Saya Minatsuki, a sweeper (licensed bounty hunter) who he falls in love with after she saves his life. His morals begin to shift because of the effect of having someone with logic and stability in his life instead of being reckless and rebellious.
His violent lifestyle before he met Minatsuki often got him in trouble. He didn't give any thoughts to the effects his actions had on other people. He mainly lived alone (his only other companions were other members of the Cronos Numbers). He realizes that he doesn't need to kill people and stops assassinating his targets and just captures them instead. One of Heartnet's friends (another assassin in the Chronos Numbers), Creed, feels like he is losing the person his friend used to be. He uses this as his excuse to murder Minatsuki. Because he believes she is the one responsible for Heartnet's retirement from the Chronos Numbers he expects Heartnet to be grateful and return to the way he used to be but instead is furious with Creed and threatens to kill him if they cross paths again. This fuels Heartnet's resentment for Chronos and other members of the Chronos Numbers.
Prior to meeting Minatsuki, Heartnet is often aggresive towards other characters. Other times it appeares that he sincerly gives zero cares. He shuts out his emotions so they will have nothing to use against him. If I had to pick the most accurate adjective to describe Heartnet at this time, I would choose defensive.
After encountering Minatsuki and facing his fate changing epiphany, he is less isolated. He still prefers to keep his distance emotionaly from characters he dosen't trust completely or know very well.
This character helps develope