With Silvian's soul in his hand, Nial could do whatever he wanted. He was not nice enough to give Silvian the hope of escaping unscathed.
Nial's following actions were the exact opposite of that because he was ready to destroy the entire soul inside the Sacred Knights leader.
But before Nial was able to do anything, his entire body began to crackle, his skin burst open and the dark energy around him began to grow unstable.
By using the entire mana that was released by destroying the energy devouring crystals, Nial's entire being was overflowing with an unimaginably high density of dark energy.
Every single bit of mana had been devoured by his dark energy before entering the darkness domain Nial had manifested far longer than he was supposed to be able to handle.
His entire being ached heavily now that all the dark energy didn't have an outlet to be released in the outside world anymore.