Eroge and bishoujo game series from Sogna (bankruptcy 2000).

h4. Namely:

    * [[Viper V6]]
    * [[Viper V8]]
    * [[Viper V10]]
    * [[Viper GTS]]
    * [[Viper V12]]
    * [[Viper V16]]
    * [[Viper BTR]]
    * [[Viper CTR]]
    * [[Viper F40]]
    * [[Viper M1]]
    * [[Viper Island]] Vol.1-6
    * [[Viper F50]]
    * [[Viper GTB]]
    * [[Viper Paradice]]/[[Viper Langerie Black]], [[Viper Purple]] and [[Viper Red]]
    * [[Viper GT1]]
    * [[Typing Viper]][[Viper Typing]]
    * [[Viper M5]]
    * [[Viper RSR]]
    * [[Viper M3]]
    * [[Viper V6R]]
    * [[Viper V8R]]

[[Viper GTS]] was made into a three part hentai anime series in 2002 by [[Studio G-1 Neo]].

h5. Other titles from Sogna:

* Galactic Guardian Guynarock R
* Animahjong