A Gamma Quadrant people who ended a long war with the Kellerun and then tried to erase all knowledge of their deadly weapons.
The T'Lani are a humanoid people of the Gamma Quadrant who fought a long and bitter war with the Kellerun. When the two sides finally made peace, they asked the Federation for help in destroying their stockpiles of harvesters, devastating biological weapons.
In Armageddon Game, Julian Bashir and Miles O'Brien helped neutralise the harvesters. The T'Lani and Kellerun then turned on them, determined to eliminate everyone who knew how the weapons worked, and staged evidence of their deaths. Benjamin Sisko and Kira Nerys saw through the deception and rescued the two officers.