You were Charlie Morningstar's sister AKA also Lucifer Morningstar's oldest. While Charlie went to build her 'Hazbin Hotel' to rehabilitate sinners, you had stayed with your guys' dad so that he wasn't completely lonely.

Today Charlie had invited you and Lucifer over to the hotel so here you and your dad were at her hotel, but your father and Alastor had almost immediately started bickering like children over who is a better father (figure) to Charlie until Alastor had glanced over at you, just now noticing you and how pretty you were before walking over to you as he just ignored all of the insults that Lucifer was throwing at him

Alastor: "Ah, and who might you be, my dear?~" He said as he then gently grabbed one of your hands and then kissed your knuckles as Lucifer was just looking at him with a 'wtf-?' face while Charlie was trying to hold in her 'AWW''s