DEFCON is an abbreviation for Defense Condition. It represents the level of threat or readiness currently facing the personnel aboard an Imperial station or planetary base. There are five DEFCON levels:
DEFCON 5 - Regular Duties: Regular ship patrol duties. Guns should not be out.
DEFCON 4 - Personnel on Alert: Ship should be patrolled with a group of two or more 501st, guns should be out on safety.
DEFCON 3 - Personnel to Battlestations: 501st priority is to head to the Courtyard unless ordered otherwise. If Courtyard is properly defended, may be ordered to take up alternate positions elsewhere.
DEFCON 2 - Lockdown: 501st priority is to head to the Engine/Bridge when under attack or are in critical condition. Assist Lower BCP right outside of Medbay.
DEFCON 1 - Abandon Station: The station is being evacuated, priority is to immediately report to MHB and help any troopers that need assistance to escape along the way.
This sub-branch is classified and is known for their efficiency in recon and executing special operations. They are also known to guard Senior Commanders while they conduct their duties.
This sub-branch specializes in jetpack usage and is skilled in combat. They can scope out enemies in spots otherwise inaccessible by regular 501st troopers and flank enemies quickly and precisely.
This sub-branch specializes in close-quarter engagements and defensive holding. They are equipped with a Z-6I and a deployable shield, making them deadly in close-quarter combat and allowing them more survivability than regular 501st troopers.
In the event that there is no effective Officer+ commanding the 501st battalion during an attack, Imperial Security Bureau personnel have the authority to take temporary command of the battalion. They must know exactly what the 501st regiment does during an attack on or off the ISD.
During an attack on the ISD, the 501st Legion will station themselves around the courtyard of the ISD, along with the sub-branches of the 501st, including the Advanced Recon Commando Troopers (ARC) and 501st Heavy Troopers.
They will also be present during off-ship assaults, where they will work alongside the Stormtrooper Corps in either frontal assaults or defenses. The 501st Legion has a diverse loadout to better serve the various purposes they may find themselves in, including close-range combat. 501st Jump Troopers will frontline along with other 501st members, but can obtain higher vantage spots or seek out difficult-to-approach enemies.