Part 179: Regarding Witches

The definition of a witch is vague, but the most accepted theory is that one is a witch at the point when they gain a power surpassing humans and are able to use it freely.

And the world - or possibly fragment - in which that can be freely used is called their "territory". Most witches cannot leave their territory, but those who are capable of transcending its boundary at will and wandering the fragments are called "voyagers".

In the story, Bernkastel and Lambdadelta fall under this type.