My favourite quote, on the creation of Los Zetas (staffed with Mexican paratroopers) by the Gulf Cartel:
They were incredibly effective as enforcers for the Gulf Cartel. So much so that at some point they decided to just take over the operations. That’s why I ask you to never keep tigers as pets.
I have always seen the Shadow Cartel as an Imperial organization, centred on Hebrin subsector, with strong ties to various cyborg underground groups and a few inherited Abadani revolutionary units, currently reaching out to the Blood Vargr of the Hegemony for extra muscle. They were successful enough to extensively corrupt the Hebrin Admiralty before being found out, with Ducal forces regaining control of the Admiralty and then Hebrin system space (including the vital ice ship lines).
This is in contrast to the very humanistic pirates of Udusis subsector, or the urbane and exceedingly wealthy Vargr/Vilani professionals of Ikon.
As for pirates hiring out mercenary groups, and the links various insurgencies may have with assorted pirate groups… that’s for the Referee to decide.