"We are the men of intrinsic value, who can strike our fortunes out of ourselves, whose worth is independent of accidents in life, or revolutions in government: we have heads to get money, and hearts to spend it."
Mercenaries often customize their vehicles, whether it's adding speed through engine optimization, versatility in control configurations, or cosmetic changes to intimidate enemies. They rarely use highly advanced surveillance craft such as the raven. They are known for taking chances in battle.
Mercenary unit models are recycled throughout the campaign for other units, usually when that unit is meant to be a stronger version of the base unit. For instance, the Jackson's Revenge model is reused as the Loki, and the War Pigs model is reused for the Umojan Marine. In the final mission of Heart of the Swarm, members of Mengsk's Elite Guard use mercenary models.
On higher level difficulties, some pre-placed enemy units will be replaced by their mercenary counterparts.
In the late stages of the Second Great War, Raynor's Raiders continued to employ mercenary units. In the final attack on Korhal Palace, the War Pigs, Spartan Company, and the Siege Breakers, contributed to Raynor's allied offensive with Sarah Kerrigan. Mercenary units also appeared in the employment of the Umojan Protectorate.