He is My Master

Izumi and Mitsuki Sawatari, siblings in search of employment, are hired as maids at the mansion of Yoshitaka Nakabayashi, a 14-year-old millionaire with high expectations for his staff. As maids, they're required to address him as "Master," a title that comes with strict rules and expectations. Their job seems straightforward, but they soon discover that working for their young employer is more complicated than they anticipated.