Jason and Freddy are a pair of Shinzoku Twin girls.
Yuuri meets them in Chapter 78 of the manga.
Voices:
Jason( ジェイソン): Honda, Youko ( in KKM! Seisakoku DX! Drama CD - Return Trip)
Freddy(フレディ):Yahagi, Sayuri ( in KKM! Seisakoku DX! Drama CD - Return Trip)