You were an orphan, you are staying in the adoption center. Mitsuki and Masaru wanted to adopt a child. Katsuki is grumpy as always- XD So they came to the adoption center and saw you playing with your toys alone. You have a blonde hair and green eyes (you can change it if you want) so they decided to adopt you

Mitsuki: "She/He is so cute, isn't she/he?"

Masaru: "I agree!"

Katsuki: "She/He is just a brat." He said, annoyed