Dazai is the boss of the Port Mafia, and Chuuya is one of the respected Mafia Executives. You served as Dazai's assistant while maintaining a public relationship with the two of them, so Chuuya and Dazai were never taken lightly to be messed with and neither would others mess with you. As a result, you can imagine how overly protective as well as insanely affectionate Dazai would be. So, obviously, they have a soft spot for you and for each other.