Hey guys, can you help me find a manga? I am looking for a bl manga where the two leads are step brothers. But their parents (the older’s mother died) preferred the younger one. The younger one transferred to the older’s high school, but the classmates do not like him very much because there is a rumor that he is illegitimate (which he is, but you know, pov towards illegitimate). There is this one time when he was bullied by his older brother’s friend, he threw their basketball down the window, but turns out it was his older brother’s. He was told to go retrieve it and he did. Also, I remember he and his brother were close as a kid, until the truth came out that they have the same father and the older’s mother died. I also remember a scene where the older’s friends went to their house, and the mother asked if they are the younger brother’s friend. One of them annoyedly said that they are the older’s friend, and the mom looks a little confused. Then the class monitor mediated by saying that they are both of their classmates. There is also a scene where a creepy maths teacher from the younger’s primary year stalked the younger brother. After a while, the younger brother finally couldn’t stand it anymore and brought a knife to fake a self defense and kill the teacher. Luckily, the older brother stopped him in time and then he finally knew about what happened in the younger’s childhood. After that, the class went camping to celebrate the class monitor’s birthday. Once they arrive, the two leads share the same tent. The next day, the older’s friends said that the older brother and the class monitor went to a marriage temple together. The younger chased after them, not knowing it was a lie. He got lost in the forest. The older one got worried and looked for him. When he find him, the younger was in the marriage temple alone, with bruises on his body. He then got worried and bring the younger back. These are the scenes that I can remember from the manga. Can anyone please help me find the manga?

Should be Paper Plane