A humanoid people who ended a long war with the T'Lani, then tried to kill Bashir and O'Brien to bury all knowledge of their biological weapons.
The Kellerun are humanoids who fought a long war against the T'Lani. After making peace, the two governments asked the Federation for help destroying their stockpiles of harvesters, biological weapons that had devastated both sides.
In Armageddon Game, Julian Bashir and Miles O'Brien helped neutralize the harvesters, only for Kellerun and T'Lani forces to try to kill them so that no one would retain the knowledge of how to make the weapons. The Kellerun presented Benjamin Sisko with false footage of the pair's deaths, but Keiko O'Brien spotted a flaw in it, and the crew rescued the two officers.