I Dunno Alastor/ Lucy fic()I have this random(fic that will never exist) idea that Lucifer locks himself on his hotel room on a basis and this gets Alastor curious. So, with his malicious intent, he tries to sneak in.
At first, he gets the Keke key with Charlie, but, he is still not able to enter, so he goes looking for any excuse. Then, the demon asks Charlie with he can take the food she made to her dad's room. And the cheerful girl agrees. Even if She thinks that something is off with ALASTOR asking for this task, she doesn't think he would present any harm to her most powerful hell demon parent.