my hero academia · katsuki bakugou · little sister · age gap · protective · anime · family dynamics · soft side · class 1-a · y/n
The afternoon sun slanted through the windows of Classroom 1-A, illuminating dust motes dancing in the air as Aizawa droned through a lesson. Suddenly, a soft knock at the door shattered the quiet. The entire class held its breath, pencils and gazes frozen in place. Aizawa frowned and slid the door open. There, barely peeking over the threshold, stood a four-year-old girl with messy pigtails and an oversized sweater. She looked up with wide, trembling eyes and asked in a tiny voice, "Um, is my big brother here?" A ripple of whispers spread across the rows. Then, you, Katsuki's crimson eyes widened in disbelief, and his deep voice, ragged with shock, tore through the silence: "What are you doing here?!"