Imperial Security Service (Vierzland)
| Imperatorischer Sicherheitsdienst (ISD) | |
 | |
_-_3.JPG) The former ISD campus, now the main offices of the Ministry of Agriculture | |
| Agency overview | |
|---|---|
| Formed | 9 May 1920 |
| Dissolved | 10 January 1990 |
| Type | Secret police Intelligence agency |
| Jurisdiction |  Vierz Empire |
| Headquarters | Trausch Building, Adtrus |
| Motto | Sicherheit in der Heimat Security in the homeland |
| Employees | 112,654 (1989) |
| Agency executive |
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| Child agency |
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The Imperial Security Service (Vierz: Imperatorischer Sicherheitsdienst, ISD) was the official secret police and intelligence agency of the Vierz Empire from 1920 until its abolition in 1990. It was one of the largest, most prolific, and most effective security services in world history. It has been described as a state within a state due to its influence on Vierz politics and national security matters for seven decades.
The ISD was founded in 1920 by order of Emperor Alexander II in the aftermath of Vierzland's defeat in the Frontier War, which had provoked widespread domestic turmoil. It was a cabinet-level agency, but operated outside of the cabinet's purview and was responsible only to the Emperor. Its main tasks became domestic surveillance, foreign intelligence gathering, and internal security.
The ISD gained a reputation for brutality and terror. During and after the Great War the ISD was responsible for crimes against humanity and war crimes, such as the Red Cleansing, which left over 500,000 people dead. During the Silent War it operated pervasive spying and support networks to support Vierzland's geopolitical goals, often cooperating with and supporting terrorist organizations to do so. It used torture, psychological warfare, and assassinations to eliminate political dissent. Over 500,000 Vierz citizens were surveilled, detained, imprisoned, tortured, or killed by the ISD during its existence. During the chancellery of Jens Pohl, the ISD operated death squads that performed extrajudicial executions.
The Vierz Revolution of the 1980s brought an end to the ISD. Chancellor Heinrich Werner dismissed the agency's last head, Baldur Katzenbach, in 1989 and did not appoint a successor. It was formally abolished with the dissolution of the Vierz Empire in January 1990. Many of its senior officials were tried and sentenced for crimes against humanity in the 1990s, but others gained clemency or fled the country to avoid prosecution.