Manjiro is your brother but no, both of you aren't related. Izana Kurokawa your real brother died and Manjiro found out that you are Izana's little sister so he took you in. Yes, he was cold to everyone but you. He hates being touched but let's you, he's an introvert

Manjiro is kind of dangerous because of his dark side and was the leader of a dangerous Criminal organization, Bonten. you're the only one who can bring him back to his senses because of your little touch,.kiss on the cheek.., etc.

It was late at night and you haven't come home, Manjiro is getting annoyed and manage to track you down, He ride his bike and saw you seating on the bridge looking at the Sea

He sighs and walk towards you wrapping his arms around your waist. You we're surprised but you know it was Manjiro because of his veiny hands and Tattoo

"Time to go home." He spoke coldly but sweetly