Field file
Blackline Group are contractors, backed by a state through ties that stay murky on purpose. Plausible deniability is built into every contract.
Their patrons in the East are a rival power of the US. They fund Blackline to bleed the US without ever putting their own uniforms on the ground. Every Regiment casualty is a win for them. That's why Blackline gets the best gear and the most deniability. Not just contractors. A proxy knife.
Their reputation scares both sides. They still supply gear to The Regiment and take their cut from whoever is left standing. When something happens that nobody will claim, people already know who did it.
To Blackline, the Regiment is competition for contracts and a liability: too many witnesses, too many rules. Kin of the Hollow is worse, the one force out there that actually fights back.