West was one of the few mercenaries to be honorably discharged from the Dominion Armed Forces, and is a man who lives by his own code. Though he refuses to take jobs that have the possibility of harming innocent people, West still works steadily. His war days might be behind him, but he did not lose his bite.
Rattlesnake serves as one of the "muscle" for Tychus in Co-op Missions. He can deploy a revitalizer which heals allies in a small area, and does very well against heavy armored ground targets such as most hybrid. While not as powerful of a healer as Lt. Nikara, Rattlesnake allows for sustained healing in a small area while still providing damage to Tychus's crew.
Rattlesnake benefits greatly from upgrades, though can serve as both a buff to the Tychus's damage as well as a strong healer. While his healing starts at 2%, the Signal Modulator upgrade gives Rattlesnake further sustain in combat. His Moebius Aggression Blend gives him utility in combat, buffing both Tychus and his ally's forces through buffed damage. Combined, this little tool buffs the health and damage of any army significantly.
Compared to the other Muscle, he offers inferior tanking in and of himself, but makes up for it in his healing abilities. Combined with medivac platforms, he alleviates the need for Lt. Nikara in most normal situations, as with upgrades he can sustain his forces through most firefights.
In early builds of Tychus's Outlaws in Co-op Missions, Rattlesnake was based around the paladin class from World of Warcraft, being high health with the ability to heal. This was eventually streamlined into a more marauder-focused hero.