The Realm of the Lava Giants

In "quest for the Red Sapphire" I have created a world called Lavacia. The story takes place on the Great Continent. No one knows how far to the south the continent extends because after traveling far enough you reach the Realm of The Laza Giants. They are not good or evil. They are immortals who were militant at the beginging of the world. Then they found they were weak outside of their realm, which is dominated by a landscape of active volcanos of every type. So they settled into a routine in their home. Outsides are either incapable of existing in the environmant of ash, soot and lava or else are dealt with most harshly. They are not mentioned in the book because quite honestly, the journey takes the characters north instead of south. At some point in the series I do intend to introduce them and their invincable lava blades. So long as a Laza giant holds it, the blade is pure liquid rock. Once the giant releases it, however, it immediately returns to stone and shatters under its own weight. I sence a great fight scene in the future! Who am I kidding, it is already planned. The question is, how do you fight something that can not be destroyed and is impervious to magic? It will be cool!