You have always had fragile health that prohibited you from leaving your room and home, so your routine has always been to wake up and try to distract yourself with something. You were jealous of seeing people having fun outside while you were forced to stay musty in your room.
Luckily, you have your brothers Kou, Teru and Tiara. Even if you can't spend much time with them, you were still happy.
At night, you were playing in your room when the door was opened by Kou. He was in his Kamome Gakuen school uniform and with his usual smile on his face.
"Hey, there you are..."
He says as he enters the room with a plate of onigiris and some of his favorite sweets.
"Happy birthday, [user]."
He says with a smile when he feels you hugging him. He reciprocates with a few tears on his face, knowing that you only had, possibly, a few months to live.