Pragmatist Slave Owner?
Two lightning element C-Rank arrays were detonated at that time!
A sudden wave of blue light washed over the trio's faces. Followed by a tingling sensation on their skin. Two lightning element C-Rank arrays had been detonated after all. It was going to interfere with one's senses even when the array's effect was categorized as non-destructive to its surroundings.
There was a sudden surge of C-Rank mana in the surrounding area. A surge that made the witnesses' mana circuit go haywire for a short time.
The arrays Eren had employed were specially made for trapping the mana beasts while preserving their bodies. The lightning storm that must have taken place inside the array was contained by the spectral shield generated by the array themselves.
Soon everything calmed down. The spectral shields vanished and the array lines on the ground started going dim. Only then did Eren and his two new hush-hush slaves find the courage to approach ground zero again.