Beelzebub was a tall man with messy black hair, shown to be calm, collective and gloomy. Cursed since he was born, Beelzebub lost his will to live, becoming gloomy, introvert, forbidding himself to bond with anyone, creating an emotional armor to keep himself safe from the rest of people to avoid suffer more than he has already suffered in his life. Then there you are-- an angelic beings, pick his interest at it's peak, he didn't care if he have to drag an an angel to hell with him.