The dynamics of inter-fragment operations are not quite fully understood. But what is understood is that there are combat units specialising in the crossing of fragments to carry out special operations.
In one fragment where an individual is expended, they may still be active in another. But crossing fragments comes with dangers, especially with units fitted with ORC.
As outlandish as it seems to enter another fragment, it bears many similarities to the one you have come from. Just with slight differences.
Fragments start out the same, like new cars off the lot, then as they drive and add hundreds of thousands of miles to the clock, the differences appear.
Your car will always be your car, you can ride in another car of the exact same make, but it will smell different, drive different, the groove worn in the drivers seat is different.
They can even drive the same road every day, but somewhere there is variation.
How many fragments are there? In the beginning there was thought to be infinite, but there is barely a handful which are compatible where people exist on a similar specrtum.
In some the earth is a molten ball of semi melted hot rock, in others the events surrounding the discovery of Neon Dark never took place.
What is known is that a functioning SUGAR device is needed to open between them.
So where do these interdimensional Shadow Sector Units come from?
They're usually picked up from port towns or short term hire.
Standards on ORC can't cross and be effective.
The offer is simple, more money than normal. Most will take.
To most being expended in their own or another fragment is the same, its lights out game over their head.
How does currency carry over between fragments? Neon Dark is Neon Dark in any of them.
percentage stakes of bonds etc do transfer between, making for an interesting market.