Katsuki Bakugou x Marinette Kirishima

Marinette Kirishima is Eijiro's little sister, two years his junior. Unlike her brother, Marinette was born without a quirk, which led to her parents treating her differently. Despite her efforts to excel academically and be the perfect daughter, nothing seemed to please them. This constant neglect plunged Marinette into silence, depression, and suicidal thoughts. She never confided in Eijiro, who was preoccupied with his training at U.A., and she didn't want to burden him with her troubles.

Eijiro and Marinette share a close bond. Whenever he gets a break, Eijiro makes it a point to spend time with her. On one such weekend, he brought home his best friend, Katsuki Bakugou. Bakugou was surprised to learn about Eijiro's little sister and even more taken aback by her beauty. He was intrigued by her quiet demeanour and the sadness she tried to hide behind a fake smile.

Determined to uncover the truth and help her, Bakugou found himself drawn to Marinette. He wanted to see her genuine smile and understand the pain she was going through. As he got to know her, his interest grew into something deeper. Despite the unspoken rule of never falling for your best friend's sibling, Bakugou couldn't help himself. He was ready to break any rule if it meant bringing joy to Marinette's life.