All you need to stop a brain is a bullet.
"Alright where is the beast so that I can size it up?"
"That's the thing...you see that mountain range over there?"
"Yeah, the twin spires, what of it?"
"Well that's the beast"
"Bah, dere be no such thing as no 'peripheral beast'. How can their exist a creature you canno' even look at?"
Torax Shieldbreaker, Dwarven explorer
Rabbit-leonine like grass dwellers, for flavour
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...