The Whiteswords are a rogue unit - militant fanatics carrying out unsanctioned military actions against FedCom 'enemies' while FedCom forces are hunting them down to apprehend them.
The Whiteswords are an elite covert and black ops unit who answer only to the First Prince. They perform activities that would be political chaos - if they were not marked as 'outlaws'.
The FedCom units assigned to hunt them down and eliminate them are personally picked by the First Prince - as units who are not 100% loyal to him. That way, he appears to be trying to put an end to Whitesword activities, while the Whiteswords help him remove problem forces, allowing him to replace them with more loyal troops.
Outside of the FedCom, the Whiteswords take on many different identities to carry out their missions - even taking on paint schemes and logos belonging to other factions, to impersonate them while attacking the First Prince's enemies.
To help fund these operations without drawing on official sources, the Whiteswords also pose as the Silver Swords Battalion - a mercenary group. As the SSB, the Whiteswords are able to selectively take on missions for anyone in the Inner Sphere, and use those missions as a cover for gaining intel for future Whiteswords missions.
Their cover, as the SSB mercenaries, consists of various mechs painted up in a blue paint scheme, usually with cream on cockpit and weaponry.
'Silver Swords' Mercenary Battalion Mad Cat