Resonance Bell

Effect: A small iron bell forged at a planar boundary that rings without being struck when certain cosmological conditions are met. Rings once when a planar boundary is within 300 feet. Rings twice when a Gate Keeper is present. Rings three times when a Divine or Lower realm creature has fully manifested in the Material within 500 feet. Rings continuously when an active planar portal is within 100 feet. Cannot be made to ring by striking it.
Uses: Permanent.

About

Made by a scholar who was tired of being surprised by planar incursions. It occasionally rings for reasons the user cannot immediately identify, creating a different and arguably worse category of anxiety.

Carries the resonance of The Silver Roads