Fiery Wrath was originally created to clear brush for farming and to demolish wooden structures with a minimum of work and no hazard; it is also used to start bonfires for rituals and celebrations. The spell allows you to destroy a building or other structure by appealing to the excitable Fire kami within the target's materials. All flammable materials within the area of effect immediately catch fire and burn until nothing but ash is left. The fire cannot be extinguished except by magical means; mundane water, sand, and other retardants will have no effect.
Only one structure may be targeted by the spell, and the fire will not spread out to the adjoining structures, as your prayers keep the Fire kami under tight control. Living beings and materials that are not flammable are not affected; in fact, while clothes worn by people caught within the area of effect will burn, their flesh will not so much as singe.