I like this idea, I have a Tarrasque who does the same thing. He is in fact the god of destruction and has destroyed countless incarnations of the material plane, and Hell, and Heaven, and the other planes. With only his own home plane surviving, as it is built from the pieces of the destroyed worlds and populated by most of those killed by him. The few who don't populate his plane are the oldest gods of the new world.

Think an Epic setting for Epic characters.

He is in no way good, and actually enjoys the fear he causes. Also, while his home plane survives the destruction he causes, he does not. After the birth of every new world, the power of the destroyer eventually gathers in a new vessel. The power and intent behind it is recognized by the destroyer, no memories from the older worlds are retained.