Lower Realm Shackles

Effect: Iron shackles forged in a lower realm inscribed with entropic binding glyphs. When locked onto a creature of extraplanar origin, the creature is bound to within 100 feet of wherever the shackles are fastened and cannot plane-shift or teleport. Non-extraplanar creatures are physically restrained but can attempt STR check (TN 16) each hour. Cannot be dispelled - the binding is entropic, not magical.
Uses: Permanent until deliberately unlocked. One set, one lock, one key.

About

These work not because they are magic but because lower-realm entropy pulls things toward entropy, and a bound extraplanar entity is simply pulled toward staying bound.

Carries the resonance of The Lower Realms