Heibon na Reijou Elis Lars no Nichijou

Elis Lars, the daughter of a marquis, is an ordinary girl. Her grades are average, her personality is mild, and her marquis family's status is not particularly high. If there's anything particularly noteworthy about her, it's that her servants are exceptionally skilled and loyal. The crown prince, who wanted to make them his aides, gets a glimpse of Elis's extraordinary qualities when he's in a pinch. The twins, the Deputy Director of the Ministry of Magic, and even the "Mad Dog Butler" all swear loyalty to her, but what is the true identity of Elis?! A peerless love story between a (not so) ordinary young lady and a perverted butler in another world!

(Source: Kodansha, translated)