Although he done a lot of bad things but is also because he keeps getting abandoned by his family.
His whole life he was never show like love maybe only lilith love him and who can help it if his become like a cruel person his father only showed him cruelty and his only parent is the queen of hell.
And everyone just from young assume he will be destined to be evil and crap. Like if you were a baby and u accidentally killed flowers and living thing who would blame the kid? If people keep implanting thoughts of him to be bad how good can he really be man his like a really sad villian.
So if you think abt it in his shoes his like the saddest life in the show. Feel bad for this antagonist.