The Complex is a huge prison located far underneath Stem Tower. There are only three ways to access it: The Stem Tower elevator with the correct clearance, the heavily guarded Stemrail line that goes from The Complex's Marks vault to the Nexus' secondary vault, or the several large tunnels that connect to Stem City's Marks mines.
The Complex has two purposes: harbor criminals that are penalized via time instead of Marks, and securely contain and protect the nation's physical interests.
There are two vaults housed inside of The Complex: The Marks vault itself is kept very secret, only authorized Stem Tower employees and specialized Lawmen know about its existence. The less important vault is known as the "Contraband Safe". It's a huge reservoir of illegal items that find their way onto Stem Island one way or another. These are usually sold off to off-world companies.
There are two central prisoner containment areas: Light containment is a more generalized holding area. Each cell is completely isolated from the outside world, minus the two holes meant for entry and feeding time. If a Light Containment prisoner is slated to be held for more than six months for their crimes, they are automatically registered on the slave marketplace located within the Nexus. This was done because The Complex was getting far too full for Blema's liking.
Heavy containment has specialized cells for its criminals. A ten minute airlock along with an access request is required for all personnel entering and exiting the heavy zone. An automatic turret system may be turned on from the Stem Tower ruler's personal computer in case of a prison break or desired execution. This gunning system will have the turrets attempt to rip through anything they see moving.
Lawmen Type-2 and Type-3 are all under The Keeper's watchful eye, a continuously cloned manager for The Complex. They're in charge of making sure everything is in working order and secure.
Operation COMPLEX was conceived, planned, and executed by the second Stem City ruler in order to combat the rising number of terrorist groups and the various attacks on Stem City depots. The operation took a grand total of 16 years to fully plan and complete, the operation only ending after the fourth Stem City ruler was in power.
After The Complex was complete in XX539, the DIGITALIZE ACT was penned. 98% of all physical Marks gold currency were collected by Stem Tower and the Markcards system was put into place.
The Complex remained the same until Blema Von Voldark's DECENTRALIZATION ACT. One portion of the act was dedicated to introducing the Nexus' digital slave marketplace. This was both to boost Stem City's chaotic economy and to clean out the high number of people Lord Frie had locked up for protesting.
Imine Green of XX534 was removed from heavy containment for Operation CHAINEDSLIME. She escaped soon after and remains the only fugitive who has escaped from heavy containment.
In XX820, the currently held prisoners contain the likes of Gunker Garrison and Romeo J. Spearhead in light containment, and Stichety Hackgone in heavy containment.