Kage No Gundan 影の軍団 is a very famous classic Japanese TV series. It talks about various generations of Ninja Army leader Hatori Hanzo 服部半蔵. There were also some Kunoichi in each army. They were beautiful but eventually sacrificed their lives for their mission.
Thank JMaruyama for having a detailed English article about this great work. You can read it at http://beyond.japanhero.com/samurai-ninja/kage_no_gundan.htm.
Let's see how a female ninja was sacrificed in a mission:
(Kage No Gundan IV, Episode 27)
You can also visit the following sites to know more about this Shadow Army: