Feed the Demon
There is no need for warfare, no need for pacts with Demons of the same recourse.
All that is required is that ones enemy be fed to their own Demon, the one that has attached itself to them, the one that stole life force from others and that will now feed upon its host.
The one that called it forth into the world, influenced by the lies of all demonic force's, that if you side with them, if you agree at any level to their terms of so called empowerment, in hope of riches, glory and control, that eventually you to will meet your demise by the claws and lips of that which deceived them.
In this way the debt is balanced, the demon satiated, the enemy destroyed and the Shaman/Magician free to wander all Three Realms as he pleases !