Sayoko Souma is one of the four Souma Family sisters.  She works on a part-time job as a tutor.

Episode 1 
 
Souma Kurumi no Idenshi - Kurumi's Gene 
Souma Delivery 
Souma Taxi 
 
Episode 2 
 
Souma Kurumi no Hahaoya 
Souma Kurumi no Zansho 
Kachou Souma Souko Step 2

[Website 1](http://ryoko-teduka.net) | [Website 2](http://megumi-tateishi.net) | [Blog](https://ameblo.jp/tezuka1015) | [Twitter 1](https://twitter.com/1015ryouko) | [Twitter 2](https://twitter.com/1015tateishi) | [Wiki (jp)](https://ja.wikipedia.org/wiki/%E6%89%8B%E5%A1%9A%E3%82%8A%E3%82%87%E3%81%86%E3%81%93)

She is a Japanese (primarily) adult game voice actress.