However I really feel I have to post something now. Posting about the Brocade Guards (Jǐnyī Wèi 錦衣衛) of the Míng emperors has been on my to-do list for quite some time now. Unfortunately I really haven't been able to do any personal research, so the following is mostly a summary from the Wikipedia.
The Jǐnyī Wèi were also tasked with collecting military intelligence on the enemy and participated in battle planning stages. A Brocade Guard donned a distinctive golden-yellow uniform, with a tablet (pictured) worn on his torso, and carried a special blade weapon.
In 1393, the Hóngwǔ Emperor curtailed the Brocade Guards' powers after they allegedly abused their authority during the investigation of a rebellion plot, in which about 40,000 people were implicated and executed. When the Yǒnglè Emperor ascended to the throne, he was afraid that his subjects might be discontented with him, because he came to power by usurping his nephew's throne. He reinstated the Brocade Guards' authority to increase his control over the imperial court.
In the later years of the Míng Dynasty, the Brocade Guards were placed under the control of the eunuch faction. As the government sank into corruption, the Jǐnyī Wèi was constantly used as a means of eliminating political opponents through assassinations and legal prosecution.
The Jǐnyī Wèi was eventually disbanded by the Qīng in 1644.
The Jǐnyī Wèi feature prominently in fiction set in the Míng. The 2010 film 14 Blades focuses on the adventures of a group of ninja-like Brocade Guards.
Scenario seed: Both a judge and his retainers, and a grup of brocade guards are after a corrupt official. The former want to arrest and publicly try him, the latter simply want to eliminate him. The PCs are in either group and must fight both the corrupt official's bodyguards and the other party.
Alternatively, two groups of PCs could compete with each other (this would need two GMs).