Mercenary

"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."

- George Farquhar

Mercenaries are soldiers or warriors who fight for profit. Mercenaries often customize their vehicles, whether it's adding speed through engine optimization, versatility in control configurations, or cosmetic changes to intimidate enemies.

StarCraft
In StarCraft Secret Missions, numerous Zerg mercenary broods offered their services to Alexei Stukov when he requested assistance in destroying enemies of his who had collected on a dark planet.

At some point after the Brood War, numerous offered their services to the Terran Dominion to help deal with the New Trinidad Pirates.

StarCraft II
In StarCraft II multiplayer, mercenary skins for the supply depot and marine are available upon reaching level 20 and 30 respectively with terran.

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.

Data exists in the galaxy editor for hellion, reaper and medic mercenaries, but none appear in the campaign.

Wings of Liberty
In the StarCraft II: Wings of Liberty campaign, mercenaries are more powerful versions of basic units.

Left 2 Die
In Left 2 Die, Raynor's Raiders can also hire Skibi's Angels (medics), Outback Hunters (hellions) and Death Heads (reapers).

Heart of the Swarm
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.

Legacy of the Void
In the epilogue of StarCraft II: Legacy of the Void, Raynor employed mercenaries units on his journey to the Void, along with the Daelaam and the Zerg Swarm, to kill Amon.

Nova Covert Ops
In StarCraft II: Nova Covert Ops, the Umojan Protectorate hired some War Pigs during their expedition to Jarban Minor.

Protoss

 * Blackman
 * Dabiri
 * Zyrkhan

Terran

 * Rosemary Dahl
 * Hale
 * Mira Han
 * Graven Hill (also recruiter)
 * Orlan
 * Alan Schezar
 * Ethan Stewart
 * Gabriel Tosh

Zerg

 * Cardis the Destroyer
 * Empress Queen
 * Eschueta the Wicked
 * Frayne the Feral
 * Gilson the Evil
 * Mastermind Overlord
 * Meserole the Marauder
 * Morik
 * Wise Old Torrasque

Notable Mercenary Organizations

 * New Trinidad Pirates (coalition of mixed species)

Protoss

 * Blackman's Reavers
 * Dabiri's Shadow Company
 * Zyrkhan's Legion

Terran

 * Hale's Commandos
 * Kimeran Pirates
 * Mira's Mercs
 * New Trinidad Pirates
 * Raynor's Raiders
 * Schezar's Scavengers
 * War Pigs

Zerg

 * Eschutriarchs
 * Feral Guardians
 * Gilson's Oppressors
 * Meserole's Plague Bringers
 * New Trinidad Pirates
 * Swarm of the Torrasque