The Energy Shelling technique was a technique that takes advantage of the immense aura/ energy that constantly surrounds the bodies of S-rank superhumans. It compresses that energy into a protective layer, which in turn is used to increase the defence of the users.
But when this technique is perfected, and has been molded properly, it turns into something more than just providing defence, it becomes the 'Advanced Energy Shelling'. An Advanced Energy Shelling technique is one that makes use of the energy inside the superhuman's body, so drawing it from there, it receives individual and peculiar traits.
For example, Yenn's Energy Shelling technique gave her to an extent, the trait of ability nullification. (She used this technique before in Coity when Ancy had tried to use her ability on her, but was clasped in the hand by Yenn, hindering it.)
