That night, despite telling himself to sleep lighter, Juin still fell into a deep sleep shortly after closing his eyes. Perhaps subconsciously, his body knew that he would be unable to sleep well once the training began, so it decided to rest as much as possible now.
Either way, Lucifer did not care. Besides, this gave him an opportunity to check on Juin's shackled soul.
Hanging in midair with one hand dangling freely next to his body and the other being dangled up in the air by the invisible chain, the shackled soul remained as quiet as before. If the leaders of those groups that coveted Juin were to see it now, they wouldn't have known that this shackled soul contained more power than they thought.