Actually.
When the Ishikawa couple first said they wanted to tell Nana the secret of her origins, and handed her the enormous hunting horn, about two meters tall, that had accompanied her birth, Nana thought she was either an alien baby dropped from a spaceship or an adopted superpowered child.
She never expected both guesses to be right, and yet not quite right either.
She was a video game character.
No, not the kind from a dating sim featuring pretty girls.
She was the silent, righteous protagonist from an old-school Japanese RPG: the kind who hunts everywhere, smashes every chest she sees, and takes things from villagers' homes.
The kind who can only manage grunts and groans in battle, no matter how hard she tries.
And...
The game still seems to be selling well to rave reviews?
Adoptive parents: For your own safety, you must protect this secret, dear.
Smiling-eyed new classmate: Nana, there really is a point to doing this, isn't there?
Nana: (swinging her two-meter-long mallet hunting horn) Beep doo, beep doo.
The pairing should be Jiezi-ge.
A mute game character x a talkative master of meaning.
Lots of video game tropes. May also incorporate some school stories and niche horror manga/games.
Theme: Enjoy a carefree youth with your friends.
