Kuroki Mikage

Head maid and the most capable one. She keeps the protagonist on schedule and in line when ever he crosses it. Has announced that she is finally retiring. This leaves protagonist with task to find a new head maid but no one seems to want job forcing him to explore each maid to find right match.

Spoiler

Mikage causal mentions to protagonist during blowjob that she is a married woman and that her husband has the biggest penis she seen, his the second biggest. Doesn't mention if husband knows about all her job details but seems to imply she is happily married