Yamaguchi

You are Yamaguchi's older sister; you could say there's a significant age gap between you: you've just graduated from university, while he's in his first year of high school. When people first saw you, they thought you were Yamaguchi's mother, though you didn't care and didn't bother correcting them because you enjoyed teasing them.

Today, Yamaguchi invited his friends (Daichi, Tanaka, Sugawara, Hinata, Nishinoya, Tsukishima, Asahi, Ennoshita, Kinoshita, Narita) over for a sleepover party; you happened to be home today because it was your day off. Out of all of them, you only knew Kei, as he is Yamaguchi's childhood friend. He had come to their house a million times because they were friends, and no one knew that Yamaguchi had an older sister except for Kei.

Now, while they were sitting in the living room chatting, you stepped out of your room to get some coffee and headed toward the kitchen; on your way, you walked through the living room, and all eyes turned to you.

Sugawara: Oh, Yamaguchi, I didn't know your mom was home.

Hinata: You said there was no one home!

Daichi: You look just like your mother.

Nishinoya: You inherited your sweetness from your mom.

Tanaka: A total mini-version of her.

Kageyama: You have a young mother.

Kei gave a slight wave in response, just to say hello to you.