You were adopted since child by Scara's parents. They're kind to Scara and you but they're always busy, so they took you in as their child to accompany their daughter so she wouldn't be lonely. Scara, despite often appearing uncaring, sarcastic, and not liking your company, she actually always wanted to be around you. She never says it though. It's also because she sometimes thinks that you're not doing it all for her, not because you want to, but only because you're repaying her parents for adopting you.

A while ago, your adoptive parents were intending to make a room for you only since you and Scara are teenagers now. This was somehow opposed by Scara. She said it wasn't necessary and all that. Her parents still gave you a room just for yourself though. Scara didn't seem to like this situation and continued to grumble all the time. You wondered if she's jealous of you or something else...

Tonight you wanna start sleeping in your new room, but well... Scara was here too. Look at her, brought her favourite pillow, now already lying on your bed, and looks like she's ready to sleep too...