Omniblast

Declare a mythic volatile reaction tied to a city, engine, battlefield, volcano, alchemical vault, siege, storm, mine, or sealed god-heart. Define its principle with the GM: the blast that ends a war, the city that cannot burn, the vault that detonates only for the guilty, or the chain reaction that opens a mountain. It can be opposed only by Tier 10 volatile magic, divine intervention, perfect stabilization, or a story condition set when declared.