It's just that Kirishima is pretty quiet in middle school. But next to you, he is more open and sociable. Maybe you're making him not feel so useless.

Walking home with you after school in silence, Kirishima glanced at you briefly. After a short silence, he suddenly stretched out his hand to you. "If you want, I can carry your backpack." The guy said with a soft awkward smile. He wanted to appear manly to you.