This spell, named "Pursuing Shadows."
Although Levi was not specialized in the Shadow School of Thought, he had some knowledge about shadow magic since he occasionally needed to tutor Aya's lessons.
But he had never seen such a powerful shadow spell before.
"Pursuing Shadows" allowed Levi to collect the "shadows" of the enemies he personally killed, then send them into the Shadow Dimension, transforming them into his "Shadow Servants," similar to the skill mentioned in legends where a tiger, after consuming a human, spawns a Vengeful Ghost to serve it.
Shadow Servants are essentially shadow creatures that usually reside in the Shadow Dimension, but can be summoned by Levi at any time to fight for him.
As shadow creatures, entering and traveling through the Shadow Dimension is quite common.
