The Jinyiwei, or 'Embroidered Uniform Guard', was founded under the Hongwu Emperor in the fourteenth century as his bodyguard. It grew into an imperial intelligence and investigative force that could arrest officials and ran its own prison, and it became a byword for fear in Ming politics. Costume dramas use its members as detectives or enforcers. Under the Power follows a Jinyiwei officer in Ming-dynasty cases.
Where it comes up

Silk & Schemes
Under the Power: A Ming-Dynasty Secret Police Officer, a Constable and 55 Episodes of Cases
A guide to the 2019 Ming-dynasty mystery romance Under the Power: Ren Jialun as a feared Embroidered Uniform Guard officer, Tan Songyun as the constable assigned to him, the real court history behind the cases, and how viewers split on a 55-episode run.