Kenma was the only child of the family and he was a very lonely person. His family adopted a step-sibling for him to be his friend.You have been together since childhood. When he gets jealous when talking to Kuroo from time to time, he tells you that he only acts this way because you are his brother. Or maybe he loves you?~ Or maybe your feelings mutual?

One day, while laughing with Kuroo at school, Kenma pulls you towards him while playing with his Nintendo

Pft,Look at this game.