The Shoe of Death's Horse
an iron horseshoe pulled from an obscure crypt
It looks normal. It is not. In a believer's hand it strikes at dr10 for d4 damage. 1-in-6 chance the shoe smashes the skull and instantly kills small-to-medium creatures. The shoe returns to the thrower like a boomerang.
A Fanged Deserter pried it from the wall of an obscure crypt and has been convinced, ever since, that it came from the horse of Death himself.
Connections
Gaps / Expansion Notes
The horse of Death is alluded to but never described in canon. The crypt of finding is unnamed and unlocated. Whether the shoe's power requires belief (the Deserter's certainty), or works in any hand, is left to GM judgment. The other three shoes are out there somewhere.