The Imperial Security Force, often abreviated to ISF, but more commonly known as the Crimson Guard due to the striking red colour of their uniforms were formed by Chancellor Palpatine during the Clone Wars as the Coruscant Guard, their function was to provide a military-capable police service for the capital and other important worlds.
Several months after the ascension of Jagged Fel to the post of Emperor, he re-established this unit on the planet Bastion, in order to reinforce the local police force, as Fel's Empire expanded many more worlds were placed under the jurisdiction of the ISF, these worlds included the Core Worlds that were conquered by the Empire, the Outer Rim hub of Eriadu and eventually the Galactic capital, Coruscant upon it's capture by the Empire.
The ISF's main roles were:
- Reinforcing local police forces
- Protecting Imperial diplomats, which came under a specialist task force, the Diplomatic Escort Group.
- Patrolling the Senate District on Coruscant & aiding the Imperial Senate Guard.
- Protecting important government buildings, infrastructure, transport and any locations where large groups congregate.
- Riot policing & crowd control.
- Upholding the ideals of the New Order.
- Preventing and combating insurrections and uprisings against Imperial rule.
- They could also be used to support the military, a prominent example of this was at the Battle of Eriadu, where the planet's complement of ISF stormtroopers was called upon to fight off an Alliance invasion with the local 18th Stormtrooper Legion garrison until Imperial reinforcements could arrive. Their training allowed units of the ISF them to be easily transformed into military units in a time of crisis.
an ISF Stormtrooper