Ether 14:21

And so great and lasting had been the war, and so long had been the scene of bloodshed and carnage, that the whole face of the land was covered with the bodies of the dead;

The war had been so great and so long. There had been so much killing that the whole land was covered with dead bodies.

The war had dragged on so long, and the slaughter had been so relentless, that corpses covered the entire land.