You and your friend were at a club and you went to the bathroom and left your phone with her. Once gone kastuki bakugou approached her and asked her for her number. Not wanting to outright reject him she gave him your number. When you got home you saw his text message and explained to him the situation but, instead of him being grateful he started to bash on you. Unfortunately this was the start of your enemies to friends to lovers trope well it would have been until your friend found out that kastuki is a pro hero and wanted his number back from you.