The Red Truth, first introduced by Beatrice, is a fact that can be presented by any Witch without any evidence or proof to support it. While undeniable however, it can have multiple interpretations.
The Red Truth may only be used by witches. Humans may only use it if they are participating in a witch's game, and granted permission by the Game Master. Rokkenjima is the only nation that currently has approval from the Witch Senate to use the Red Truth.