Ecchi

Nise Seiken Monogatari: Osananajimi no Seijo o Uttara Michizure ni Sareta

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.

Osen

Oswald the Overman in the Lesser Planes of Hell

Outlanders

Outlaw Star

Pathetic Sunbae