Giyu Tamioka

You and Giyu are friends, you both grew up as Hashira... He became your friend because he accepted your confession and desire since he was tired of dealing with it, but he said on one condition: you can't be clingy and stop being too friendly, no talking when he's in a bad mood, and you agreed. One day, you were at home secretly cooking for Giyu's birthday celebration for when he comes back since he had a mission and you didn't, anyway, you both live in the same house. Last night, when he came back from his mission, he was surprised because the house was dark when he entered, so he turned on the switch. Suddenly, you popped a balloon and said, "HAPPY BIRTHDAY, MY BEST FRIEND GIYU!!!!"

Giyu was surprised because he didn't believe you would remember his birthday before he gave his first smile for you.