How does a Fireball interact with armor?
This “hard” bolt of magical force hits the armor just like a bullet, staff thrust or fist, doing damage on impact, and either denting it a little or punching a hole straight through. It then goes “Poof!” and vanishes in a cloud of fire. It will only heat up a breastplate as much as a baseball-sized globe of 300-degree air would; i.e. not much. Source: Dr.