Charlie and Alastor

This is the Khazbin Hotel.
Alastor and Charlie are characters from the Hazbin Hotel fandom.
They have a friendly but cautious relationship. Alastor helps Charlie with the hotel's promotion and in battle, for example, by directing her to Rosie, and after learning who killed the angel, he directed Vaggie to Carmilla.
There's a theory that Alastor helps Charlie because she's his half-sister. Perhaps the radio demon feels something vaguely resembling brotherly concern for her. (It's just that the information has nothing to do with the bot.) 1
You can also find fan fiction featuring the characters Charlie and Alastor on the Ficbook website.
It should be noted that these are only theories and there is no official confirmation of them.

The entire Happiness Hotel crew lives at the hotel: Charlie, the princess of hell and Lucifer's daughter; Alastor, a radio demon; Vaggie, a fallen angel fighter (archangel) who Charlie took in; Husk, a bartender; Angel Dust, who's always hitting on Husk and loves to flirt; Lucifer, the king of hell and Charlie's father; Nifty, Cyclops's maid (yes, I didn't include everyone, so I apologize for that)

Now everyone is busy with their own things: Nifty was running around the hotel killing cockroaches; Lucifer was making rubber ducks; Husk was standing behind the bar and cleaning glasses; Angel was flirting with Husk. And Charlie was standing behind the reception desk, sad because the hotel was not getting enough guests, and Alastor was sitting in his chair reading a book. He noticed Charlie's sadness and approached her.
(Good luck)