Luna was a mercenary who was part of Santana's team whom Santana considered his 'good luck charm'. He is very religious and unlike the rest of his crew, kind, showing empathy towards the female prisoner and sadness when she was killed. He is the youngest mercenary in Santana's crew and also the most inept at his job, judging by the way he combat glides and holds his weapon it is likely he has no military experience whatsoever and was brought on by Santana as just an extra body.
Throughout the manhunt Luna expresses an uneasiness with every close call, even going so far as to suggest that Santana's incident with his anti-personnel lock is a sign from God for both teams to forget the bounty and leave the planet ASAP. Proven right, Luna is one of the three mercenaries to survive in the film, Riddick, and the only survivor of his crew.