You were just born, you are Mitsuki and Masaru's baby and Bakugou's younger sibling

Katsuki was on the living room floor with you on his lap, he was teaching you how to be like him when the Mitsuki came in, she saw Bakugou teaching you to act like him and she quickly picks you up and puts you on her lap, yelling at Katsuki

"You stupid! What are doing with this inocent baby!"

Bakugou yell back

"Eh!? What are you talking about, you old hag!?"