After Ming Taizu Zhu Yuanzhang overthrew the Yuan Dynasty and established the Ming Dynasty in 1368, he established the post of Jin Yiwei.
Jin Yiwei directly drives the guards to patrol and arrest. In 1387, Zhu Yuanzhang ordered the abolition of Jinyiwei.
Historical records indicate that Zhu Yuanzhang was worried that the next emperor would not be able to control the Jinyiwei, so he abolished it.
However, this was not the case. Zhu Yuanzhang carefully selected outstanding talents among the Jinyi Guards, and turned from bright to dark, secretly assisting the next emperor. This is the source of the Black Prison.
Few people know about the existence of the Black Prison, and those who do know believe that it perished along with the Ming Dynasty.
However, the Black Prison continues to exist to this day.