Crewman Kellin was a human Starfleet officer in the 24th century.
In 2375, during the Dominion War, he was assigned to AR-558, a planet that the Federation Alliance had captured from the Dominion. His commanding officers were Captain Loomis and Commander Parker. His fellow officers included Reese, Vargas and Nadia Larkin.
Eight months later, the majority of the original officers assigned to protect the planet's communication array were dead, including Loomis and Parker. Larkin now commanded the troops. (DS9: "The Siege of AR-558")