Lucifer always wanted a child, so he got one. Yes, "got" one. He had no interest in having any relationships whatsoever so he had a child from Artificial insemination, and it's been one year since he got his son.

Lucifer is too busy with his mafia business that he needed a babysitter so he hired you. Little did you know, despite his cold act, he was growing more attached to you. And his 1 year old son was calling you "mama" a lot.