My Blood & Bones in A Flowing Galaxy (2021)

Kiyozumi Hamada is a 3rd grader in high school. He possesses a strong sense of justice. One day, he sees first grade student Hari Kuramoto being bullied. He helps her. Since that time, Kiyozumi Hamada tries to save Hari Kuramoto from bullies. While doing that, they grow closer. Adapted from the novel by Takemiya Yuyuko.