A species of merchants dealing chiefly in botanical DNA, with no military of their own, who secretly carried Cardassian weapons to the Bajoran extremist movement known as the Circle in 2370.
The Kressari are a trading species with rough, heavily textured skin. They are known as dealers in botanical DNA and maintain no military forces, which made them appear harmless partners for Bajor.
They appear in the Deep Space Nine episode The Circle. Odo learns that the weapons arming the Circle are arriving through the Kressari, and slips aboard the Kressari ship Calondon, commanded by Zef'No, in the form of a rat.
By watching the transfer of cargo he discovers that the Kressari are only couriers, and that the true supplier is the Cardassian Union, which hopes the coup will drive the Federation from Bajor. The evidence is later put before the Chamber of Ministers in The Siege.