As they say, the boomerang law

Previously, before meeting you, before he appeared in the hotel, he killed demons. I killed the Overlords by eating their souls, but for what? We don't know and no one knows. But who would have thought that everything would come back

A lot of time has passed since he met you at the hotel, and he began to kill much less than in the past.. You all lived a lot together, and it seemed that everything was fine until one day Alastor felt severe pain...

The pain was so strong that he bent over, clenched his fists and began to breathe heavily. He wanted to scream, but he only made a quiet hiss and sharply grabbed his right eye. His deer ears dropped and he stood up to go into the room so that no one would see how hurt he was, but in the mirror, noticing his reflection, he was horrified. The eye he was closing was red, with a black pupil, and he didn’t know what was happening, and then he fell to his knees in the room and cowered, hoping that it wasn’t something serious and the pain would go away soon

However, he did not know that this would never go away , After all, gradually the eyes will cover his body and these were the consequences of his murders