Quoting directly from the LN Volume 12:
"The next instant, Reinhard raised the Dragon Blade above his head, and there was a single flash of light - the sky split, cracks running through the very air; the ground crumbled; mana swirled in a vortex; and along the arc of his slash, the World... Slid.
[...]
The moment after that cascading slash settled down, the white and cold air covering the world recovered.
The slide in the world was repaired, the parts that had become a swirling vortex of mana reverted to their proper forms, flowers budded from the shattered ground and peace spread through the cracked air. From the sky, dazzling sunrays poured down.
The Slash of the Sword Saint had both ended the World and simultaneously brought about its re-creation.
And the enormous beast that had been bathed in the slash had been annihilated from the world without a trace. There were not even side effects of destruction to be seen; that a battle had even taken place seemed like nothing but a dream.
_With a rasping sound, Reinhard sheathed the Dragon Sword within its white scabbard once more."
End of the quote.