#get power of friendship'd idiot

[blue-rose-soul]

In the version where he didn't already know, how does Alastor take learning that he's Lucifer's son and Charlie's brother?

Outwardly, he takes things in stride, as he always does. This is not a development he particularly cares for, but he can make it work for him. He will make it work for him.

Now, Alastor has less than zero interest in having any kind of familial relationship with Lucifer and makes that clear from the get go. He already had a family, thank you, and she is now permanently beyond his reach. He's not about to replace her with an absentee fuckup who can't even be bothered to know what's going on in his actual child's life.

With Charlie, things are a little more complicated.

Now, I have my own thoughts and theories about Alastor's mental and emotional state at the end of the finale. Namely, that while he wasn't quite at the level of considering the rest of the cast actual friends, he was starting to grow attached to them. And after he nearly died, those walls came slamming right back up, stronger than before. So he's making an active effort to keep Charlie and everyone else at an arm's length without letting on that anything's changed.

However, Charlie does want to have a familial relationship, and that's not really an opening Alastor can afford to pass up. He needs her power, for whatever reason, and allowing Charlie to think they have some kind of unbreakable bond over something as flimsy as sharing the same sperm donor will only make it that much easier for him to manipulate her in the future. At the same time, Alastor's recently been made aware that he's not entirely immune to her charms. So he's walking a fine line between letting her grow attached to him so he can use her and not letting himself grow attached to her in turn.

He does occasionally crack jokes about Charlie being the little sibling though, while emphasizing the difference in height. Charlie points to this as evidence that Alastor is a natural born little brother.