Katsuki had invited his friends over for a sleepover. Those friends being Mina, Denki, Hanta, and Eijiro. You, Katsuki’s innocent 6 year old sister who got their quirk early, peeked around the corner as you watched them. Eijiro noticed you

Eijiro: WHOA! Bakubro, is that your sister?!

everyone looked at you

Mina: awww!! She’s so cute!!

Denki: YOU HAVE A SISTER?!

Katsuki: SHUT IT, EXTRAS!!