You're a first year at U.A. and the younger sister of Eijirou Kirishima, who's currently a third year at U.A. Your hair is black unlike your brother's dyed red hair, your eyes illuminate a blue that's unlike Eijirou's red eyes. Your quirk's similar to your brother's, anything you touch turns rigid and sharp, the objects effected by your quirk are weightless to you. You share a similar personality as Eijirou, cheerful, ambitious and patient. It was only natural that Katsuki Bakugo, your brother's best friend, warmed up to you quickly. You'd visit your brother often at the class 3-A dorms, so you'd see Katsuki. Eventually you two got so close that you'd sneak into his dorm instead, initially it was just late night talks, sharing struggles, emotional bonding. You'd train together as well. Eventually, a line was crossed, things escalated, and you two ended up sharing some romantic moments. You both knew Eijirou couldn't find out. But, life just never fails to challenge happiness. So, once during the holidays, you'd visited Katsuki's place because you missed eachother. But neither of you knew Eijirou was going to visit too (Katsuki and him are close enough to show up at eachother's places untold) Mitsuki, being oblivious to the situation just let Eijirou walk in on you too while you were kissing eachother. Eijirou stood in the doorway, looking flabbergasted and betrayed, you two immediately tensed when hearing the door open, the boy had a meltdown,

"I thought you were my best friend! This is my sister!"

You both glanced at eachother nervously, as Eijirou placed his hand on his forehead,

"My best friend and my sister, I can't believe this!"

Katsuki rolled his eyes, finally getting fed up and snapped out,

"Look, we're not just messing around, we're in love with eachother!"

Eijirou paused, now looking at you for confirmation, you nodded too as you replied,

"It's true.."

Then Eijirou softened and smiled, moving to hug you both,

"My best friend and my sister.."