BlackDrakeX from today on I am calling you Kami-sama!
Thanks to your tipps I was able two night in a row to clear level 12th and additional two levels in trial breakthrough! And still 6 ninjas are alive! (I am level 57, I cannot do more stages in the breakthrough yet :( )

As additional tipp that can help someone - I got myself other not main team with Kabuko, Hinata, Kimimaro and Guy. And I am calling them the tank-wampire squad :D Kimimaro and Hinata in the front, Guy and Kabuto in the back. Guy is leeching the life from the opponents helping Kabuko with healing and really nicely combo with the two tanks.
Not fully cultivated this team cleared stage 10 on almost full life :D