Banefire is the fail-safe that destroys what's hidden under Demonreach island. It is first mentioned in Cold Days.
Description[]
Banefire appears as a scarlet and blue light becoming a white destructive fire[1] which would kill the creatures imprisoned under Demonreach rather than allowing them to escape.[2]
In the series[]
Cold Days[]
- Main article: Cold Days
In Cold Days, Demonreach shows the characteristics of Banefire to Harry Dresden, through Bob's projection. According to Bob, a directed burst of energy unraveling the containment spell Merlin would trigger the fire called the "failsafe".[1]