A widescale experiment involving black holes performed in a certain state of America backfired. This backfired experiment kickstarted the "Fantasy Revolution".
When the experiment backfired, multiple artificial black holes became unstable; this caused an entire state to disappear, killing millions. In a span of a few days, the entirety of the western continent became inaccessible.
During all this, a new force entered the world: mana. From the black holes, fantasy-like elements emerged. Researchers in the continent reported that, as unbelievable as it is, they had obtained supernatural powers.
The world has entered an age of magic! Monsters from urban legends, myths and stories start appearing!
20 years later, Shiromata Kizuto is a student looking for a job in this fantasy world.
In the epic conclusion to the Devil's Deal series, Freya has one final chance to discover the full potential of her own power, and to use it to restore balance in the universe - once and for all. After the destruction caused by Roisin, Ferya and Torix come to terms with their losses and mistakes... And prepare for a final battle that will change everything.