All those held captive in the Nether Prison are extremely sensitive to death.
If not, they would have perished in the battles before their imprisonment, rather than being cast into the prison helplessly by their foes.
So, the moment it was released, it launched an attack without hesitation.
There are only two scenarios for being released: one is someone opening the prison through special means to aid in an escape; the other is...
The Nether Prison in the Star Realm is a special space, similar to the elemental plane within the entire Star Realm.
It can be opened anywhere, but requires precise nodes and a key.
This means these prisoners are held in unknown locations, unless rituals reveal their exact positions and establish a connection to unlock it with a key.
Information about the detention location is only known to those who imprisoned them.
This leads to very few truly being released compared to the number imprisoned.
Few righteous people would retain this intelligence.
