The "Gallery" of Frostwater Harbor has proven that if nightmares of the Twisted Tier are left unattended, they will continue to grow and self-recover.
According to the records of the Church of the Silver Scepter, it's not entirely impossible for nightmares to grow to a degree that directly affects reality....
And the Church of the Silver Scepter, was essentially powerless against the "Gallery."
Nightmares are not a mechanism that can be resolved simply by being "powerful." Although clergy, compared to ordinary people, have a tremendous advantage in the domain of nightmares... To everyone, nightmares are still relatively fair.
No one can guarantee they will definitely purify a particular nightmare.
The ultimate result was to dispatch a person to sacrifice—to use a life as a consumable, exchanging their own erosion for more opportunities to see the full picture of the nightmare.
