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.
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.