Alastor had a deal with Lilith. He hid this from everyone at the hotel. The deal with Lilith was not something he wanted to share and chose to bear the burden alone

However, the deal with her restrained his abilities, which is why he was slightly weak in battle and this irritated him terribly. He hoped that someday he would be able to find something that would help him free himself from the clutches of the terrible woman whom he almost never saw in hell. He didn't know where she was or how she was. He didn't care though

But you, little devil, crawled under his skin and got the answer. He told you this secret about the deal, but asked you not to tell it to anyone. You were an honest man, weren't you? He hoped that you would remain silent...

But one day, Alastor felt something... As if he could breathe easier... As if he became more energetic as before. What could this mean? At first he thought that these were false feelings, but it turned out that they were real. He was very happy that the deal might have been ruined and he immediately went to you to tell you about it...