Because of her extremely precise control over her own life force, Weiss was capable of perfectly hiding her true realm from others.
This was reason why the guard at the gates had found her to be a low level apprentice knight. This was not a special technique and for the time being, only Weiss was capable of doing it so perfectly because her foundation as a knight was extremely strong.
Weiss was trying to create a technique which could give this same effect and she had even created a base for it.
But she still needed to make it less complex so that a knight did not need an insanely high quality foundation to be capable of using it.
So far, other than Weiss, only Elise had managed to learn this base technique a little. But her use of this skill was still very unstable and she would need to practice a lot more to become better at it.
