Adult PC Game: Depths of the Old Forest - Ouka Kenzan (jap) Archive

A story of youkai extermination featuring a cool-headed and strong-willed female swordswoman.
Made with escalating ero in mind, both youkai and townspeople want a piece of Ouka.
Watch Ouka's expressions and reactions change over time, even during battle ero.

Viewing ero scenes and defeating certain enemies earns you Lewd Points,
which you can use to learn new skills, or strengthen your blade.
The level of ero proportionately affects the power of the strengthening.