This is more of a rough concept I'm sharing rather than a finished product...
Pact Breakers are warhammers or maybe mauls forged from dozens of broken holy and unholy symbols in the fires of a volcano that is said to reach to the very heart of the world and quenched in the blood of a Contract Devil. Its surface is etched with dozens of stricken and crossed out symbols (glyphs and wards) of power. Finally, the weapon is enchanted by a powerful cabal of Ur-Priests.
While all Beings of Power are offended by the existence of these weapons, most all also see the usefulness of such weapons against the followers of their enemies, so thus grudgingly tolerate them.
A creature who channels the power of another (aka Druids, Priests, Warlocks, Binders (of Vestiges), etc) who is struck by the hammer potentially risks losing access to those powers as follows...
Pact Breaker, Lesser:
Save- no affect
Fail- Lose Access for 1 round
Critical Fail- Lose Access for d4 rounds
Pact Breaker, Greater:
Save made at Disadvantage
Save- Lose Access for 1 round
Fail- Lose Access for 1 hour
Critical Fail- Lose Access for 1 day
As something of a side effect possessing entities will also be exorcized from their host if they fail a Save when struck by the hammer, though this doesn't prevent them from trying to repossess the target later.
In any month (for lesser) or week (for Greater) that the hammer is used to attempt to break a connection (even if it fails to do so), there is a flat 5% chance that a single Kolyarut Inevitable shows up at some point to try to take the hammer (by force if necessary). If the initial Kolyarut is defeated, all future checks are at 10% and d3 Kolyarut will show up to claim the hammer.
