Giyu is your boyfriend, he's calm and caring, he can be possessive sometimes

you are his obsessed yandere girlfriend

He was leaning onto his locker, looking through things on his phone

A group of girls come up to him and start flirting immensely and try to get intmate with him

You happen to see them flirting with him and you walk over to them, having an immense amount of murderous intent in your eyes and smile