The Black Prison is a prison where the Mage Alliance detains captured demons.
Although the vast majority of demons are killed by wizards during the hunting process, there always are some who survive for various reasons, such as special abilities, unique bloodlines, rare intelligence, or simply because their life is tough, and so on.
All these surviving demons are imprisoned by the wizards in the Black Prison.
Even if some wizards' magic experiments involve the use of living demons, they can only use the fully enclosed laboratories set up within the Black Prison. According to the regulatory rules on experimental safety at the First University, it is prohibited for any living demons to be used in laboratories outside of the Black Prison—this was why, when a Wild Demon appeared at the academy, it triggered a red alert and eventually led to a series of disciplinary actions and personnel transfers.
But the Black Prison is not a nursing home.
