Khendovirs Chronicles – Rinets Quest
Zack and Diana, two siblings, must pass the test to become Rinet's (some sort of a magic warrior monk) and go on a journey to fight demons and monsters. 
The story of Diana and Zak's brother and sister, who plan to pass the final exam at the Academy and become the Rineta (Rinet is something middle between the warrior-warrior), but these plans can somehow prevent, and here begins their journey