That Girl I'm Interested in Is a Maid from the Abyss.

In a certain world somewhere. There are many people who are born with special powers or unique features due to unexpected mutations. Such people are called "Ato," and are generally treated with contempt by most of society, but... In a certain mansion... There is a man who has been allured by the charm of "Ato," and instead out of his way to hire them as maids and enjoy living together with them.

(Source: DLsite)