Also known as Political Police, the Secret Police are a type of government agency that works in the shadows and is above the law. They protect the power of political leaders by imprisoning or assassinating those who show dissent.
The Secret Police in Megami Ibunroku Personaare likely employees of SEBEC, as they only appear in the company's headquarters, cannot use magic, and will not negotiate with the party. As they are hostile to the party, it is likely that their purpose is to protect Takahisa Kandori, the president of their branch and the mastermind of the DEVA System.
"A secret investigation agency belonging to the United States Department of the Treasury. As the name suggests they investigate matters secretly and are also responsible for escorting the president and preventing assassinations."