Kell was a commander in the Satedan Military.
This section requires expansion
When Ronon Dex heard that he was still alive, he arranged to see him through Teyla Emmagan. However, the second Ronon saw Kell, he killed him in cold blood. When Teyla noticed he used her friendship, Ronon explained that he left Sateda a coward by sending thousands of soldiers to their deaths to save himself and only regretted that his death was quick. Apparently even his own men agreed with Ronon's assessment of him as when Ronon told them they all knew what kind of a man he was and to kill him if they wanted revenge, they let him go. (SGA: "Trinity")
When Ronon was made a Runner on Sateda again, he remembered talking to his betrothed Melena Omi and telling her he sold all of their possessions to get her a position on Kell's staff. This would secure her passage off of Sateda, but she didn't take it and died in the invasion. (SGA: "Sateda")