[...Oh. She thought he was referring to the "Demon King" name being inaccurate.]

You must realize that your war isn't necessary. It's highly unlikely that they'll be able to deplete all of the mana, no matter how much they devour. If anything, the mana will destroy them before anything else.

[She knows, because according to the writings in the Sunbeam Ruins, it's happened more than once in Sornieth.]