Kagero is amoung rare kind of Ninjas serving that she is a woman. She spent her years as her Grandfather’s pupil until he was killed by her major enemy, the Kawagami. She fought with Tsimbaro a trusted friend until he disappeered. She now is a Ninja Wanderer following where her feet take her.
A shape-shifter of some sort has taken up a post at the War College of an enemy realm, where he secretly picks off only the most promising officer cadets, arranging bizarre accidents that gradually debase the leadership of the hostile army. In the long run, this will improve his nation's chances when the inevitable conflict comes.
As a shape-shifter he can impersonate superiors and peers alike and send the target candidate to the cleverly-prepared site of his (or her?) execution. As long as he is successful, no-one will ever know about the deception--even necromancy will only implicate the one impersonated...