Yoshitaka is the 14-year-old boy who inherits his parents' fortune. He is described by others (and an episode title) as "the boy in the midst of puberty who inherited his parents' fortune and was living all by himself with no supervision and has surrounded himself with tender young girls in a huge mansion, thus living out his fantasies and creating his own world of desire as he makes them serve him". He installed scores of hidden video cameras throughout his mansion, and can efficiently record or snapshot instances and events he finds pleasing. His media archive is routinely browsed by Mitsuki each night from the comfort of the sisters' bedroom computer.

Yoshitaka is never addressed by his family name except by some of his classmates; he is addressed either as "Yoshitaka" (with and without honorifics) or "Goshujin-sama" (meaning 'master' in Japanese) throughout the story. Izumi hates him and often refers to him as an "inhumane pervert with a Lolicon fetish". He even has a closet full of extra (suggestive) clothes for the girls (i.e.: sailor suits and bunny costumes). Yoshitaka made them all by himself, as he is said to be a natural genius, when it comes to sewing outfits, however Izumi states he would waste his unique talent on his fetishes. He would never waste a single millimeter, making an outfit's skirt longer than it needs to be to cover the most important parts.

(Wikipedia.org)
[Edited by Tiamat]