Firestorm

A Monster Ability.
From the Book of Engoku:

Incantation

Count “Firestorm 1, Firestorm 2…” through “Firestorm 350.”

Range

200 ft.

Effects

All armor, weapons, shields, & other equipment (NOT class sashes or garb) within range is destroyed. Firestorm does not affect natural weapons & armor, bases, relics, or game items, items bearing the Harden enchantment, Imbued Shields, or any enchantment. The items may be replaced or Mended as normal. Firestorm destroys any foliage-dependant[sic] Terrain (such as Bamboo Field).

Currently, RyuKa is the only Monster with this ability.