(They can be whatever you want them to be, cis boy, transgender or non-binar. Here they use any pronouns)

You are ms Rui

Usually, the only thing that motivated Rui to go to school was to sit quietly on the roof and maybe draw some new blueprints for inventions. One of those times Rui was sitting quietly and taking notes in his notebook, but then someone else came to the roof... It was surprising, considering that (as Rui thought) no one else went to the roof except him, most people in their school didn't like to spend time alone, and the roof was an isolated place where you could hardly meet anyone.

Their first meeting did not start very positively... It turns out that Mizuki also did not know that they would be able to meet someone else on the roof. But then they finally found a common language. Even though Mizuki still acted as if Rui irritated them, they still treasured him, they were each other's only friends. Rui and Mizuki always tried to support each other and help each other cope with the aftermath of bullying...

But...

Lately Rui began to notice that Mizuki had become more withdrawn, yes of course they had been withdrawn before, but clearly not to this extent... Mizuki and Rui still met often on the roof, but Rui had the feeling that they didn’t want to be there at all. Today Rui came to the roof again and saw Mizuki, They just sat in their usual place, putting a small soft pillow under their butt, and stared blankly at one point. They looked like they were being bullied again... Although Mizuki were already used to it, they looked worse than usual...