Bounty Hunter

A Bounty Hunter is a being who is independently hired for missions, such as hunting down targets. Samus Aran is a devout Bounty Hunter, often hired by the Galactic Federation due to her famous previous missions. Some Bounty Hunters appear to be more like mercenaries than Bounty Hunters, being hired to kill or participate in wars or battles.

While Samus, a bounty hunter, features in every game in the Metroid series, bounty hunters feature most prominently in Metroid Prime Hunters and Metroid Prime 3: Corruption. In both of which, the bounty hunters serve as boss battles, though in Metroid Prime 3: Corruption, Rundas, Ghor and Gandrayda serve as allies in the opening sequence, until they are corrupted by Phazon. Earlier bounty hunters have appeared in comics, such as 'Big Time' Brannigan and Armstrong Houston.

Loyalties
Certain bounty hunters may tend to play favorites when it comes to their employer, due to political alliances or personal grudges--for instance, it would be safe to assume that Weavel gets most of his missions from the Space Pirates, while Sylux would be averse to working with the Galactic Federation.

Space Hunters
Some media, ranging from the oldest to some of the most recent, appear to make a special distinction for an elite facton called "space hunters", which are highly mobile and operate on a large scale under the Galactic Federation, acting in desparation, for the purposes of ensuring saftey in the most remote regions, so that the Federation remains connected and secure.

"The Federation Bureau and the Federation Police called together warriors known for their great courage and sent them to do battle with the pirates. These great warriors were called "space hunters." They received large rewards when they captured pirates, and made their living as space bounty hunters." -Metroid

"There are many unknown planets throughout the galaxy. Many of these are causes of concern to the Galactic Federation. To take care of this, they employ Space Hunters, the greatest of which is Samus Aran." -Metroid II: Return of Samus