Ecchi

Nobunaga-sensei no Osanazuma

Nukitashi: Nukige Mitai na Shima ni Sunderu Watashi wa Dou Surya Ii desu ka?

Old in Age, Young at Heart

Old Man with the Evil Eye: An Unimpressive Thirty-Something's Harem Dominance

Onegai, Nugashite.

Oppa Husband

Osen

Oswald the Overman in the Lesser Planes of Hell

Peep

Please Go Home, Miss Akutsu!