“Kind people find that they are cruel, brave men discover that they are really cowards. Confronted with their true selves most men run away screaming!” – The Neverending Story
Bifrons was a Roman god of duality said to have had power over both portals and beginnings and endings. The god is most commonly depicted as having two heads facing in opposite directions.
The Bifrons Mirror appears to hold something of his magic.
When a Celestial looks into the mirror, they will see a reflection of whom they would have been if they were on the other side of The War. Angels may use it to sing “demonic” versions of songs (such as the Songs of Aura or Numinous Corpus: Wings), to resonate like the opposing band, or to “follow” their reflection into Hell. Demons may likewise use it to sing “angelic” versions of songs, resonate like the opposing choir, and even theoretically follow their reflection into Heaven.
The first time a Celestial views “themself” in the mirror they gain a point of dissonance, and then another any time they use the mirror to act outside their nature.
It is not clear what an Olympian would have expected to see, but most Celestial scholars suppose that it was intended to allow the Greek and Roman versions of those gods to discourse with each other even after the battles of assumption which awarded the Greek pantheon primacy.
Janus and Valefor are constantly attempting to steal the mirror from each other. Should it ever fall into the hands of a group of PCs, expect that one or both Superiors will attempt to steal it from them within the month (or possibly even sooner).
Alaemon, Asmodeus, Baal, Dominic, and Michael have each expressed an overt interest in the relic and would likely offer a sizable reward to a Celestial that delivered it (which is enough to also draw Mammon’s interest).