Tonari no Kaibutsu-kun

Tonari no Kaibutsu-kun focuses on the relationship between Shizuku Mizutani, who has absolutely no interests except in studying and her plans for the future, and a boy named Haru Yoshida, who sits next to Shizuku in class but rarely attends school. After Shizuku is tasked with delivering class printouts to Haru's home, she meets Haru, who immediately greets her as a friend, starting their new relationship.

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Main characters
Yoshida Haru
He is the male protagonist of the story. He is a high school student who attends the same school and same class as the female protagonist, Mizutani Shizuku.
He was suspended from school before the start of the manga/anime, but his suspension was over by the time the story starts.
At first impression, Haru appears to be a violent and fierce person. As the story goes along, it is revealed that his aggressiveness is a front; he is actually shy and innocent. Because of this shyness, he is not able to interact normally with other people and many students at school fear him due to his "delinquent" appearence, which results in him having no real friends and being unwilling to attend school even after his suspension ends. However, he is willing to lend a helping hand to others has shown to be quite an honest person. Haru seems to be an intelligent student, receiving grades higher than Shizuku's. This intelligence is also shown when he chooses to tutor Natsume so that she may pass the retake test. 

Shizuku Mizutani 
She is the main female protagonist of the series. She is a second year student at Syoyo High School. 
Shizuku never had any friends since she entered school, nor has she attempted to make any. She only sees studying and counting to fulfill her dream of earning 10 million yen per year important. This was changed when she met Yoshida Haru, a young student who kept skipping school because he couldn't bring himself to go. Ever since her encounter with Haru, she has started to make friends and get along with others, which eventually formed her current group of friends.