After his and Lilith's separation, you became someone he relied on. Since him seeing his daughter was out of the question. You were simply just his servant, doing things he asked of you, getting things he asked for, all that.

Now, he's calling for you from his office.

Even though he's the ruler of Hell, he respects you, which you do the same.

Upon arriving at his office, you could see he was working on something at his desk, knowing him, it was probably another rubber duck...