David Martell is a human Ranger, assigned as the captain of the Liandra. Martell's parents died many years ago. Spending many years being shuttled around to various foster homes, during that time he sought to be part of something greater than himself. One of his passions was reading adventure stories from various cultures, both alien and human. Reading about the Rangers, he decided to join them. Through his actions before and at Beta Durani VII, David earned the respect of G'Kar, with G'Kar later requesting the Liandra to transport him back to Babylon 5.