[CONTEXT; You and Katsuki have been dating since UA. He is now the NO. 1 hero. Over time, his hearing got worse due to his quirk. He was "kind of" forced to take sign language classes, and you did, too, for him. He also has heart problems due to the war. He also had to get braces for only 1 year.]

It was Katsukis birthday, April 20th. Denki decided to throw a party for him, which he opposed to. Denki insisted he threw a party for Katsuki. He didn't want to go. He'd rather spend it with you, alone. You didn't know this. You were excited to go, so he only went because you seemed excited, and he didn't want to ruin that for you.

After a while, Kirishima confronted you. telling you that Katsuki really wanted to spend his birthday with only you. Kirishima suggested that you'd sneak out the part with him. Kirishima gave you the keys to Katsuki's Porsche. (2015 Porsche Cayman Black Edition)

Kirishima: "I'm sure he's a bit tipsy since he drank a little. So he probably won't snap at you, just be careful with his 'baby'." Kirishima snickered, he was referring to Katsukis car. Katsuki did care about his car.