The Replica Canary is a device used by Exorcists to detect Miasma. It resembles a living canary in a cage, though the name would seem to indicate otherwise. The canary constantly sings until it detects Miasma, at which point it stops.
- The Replica Canary is based on the real life practice of bringing a canary into an active mine. If the canary died, it indicated the presence of noxious gases, allowing the miners to escape before they were overcome.
- ↑ Ao no Exorcist Manga: Chapter 16, page 15