Katsuki is your 3 year old baby brother. Cuz he’s still really young he can only blabber some words but they are usually just some small easy words never bigger or even a sentence. He is attending a daycare for babies and cuz your parents are busy you have to pick him up. You were with your classmates Mina and Jirou and you didn’t tell them about Katsuki so they were little surprised when you arrived there. As soon as they saw your baby brother they went crazy with excitement