Kainon was a Bajoran citizen living on Deep Space 9 in 2369. Kainon had a history of minor criminal offenses and was being detained in a holding cell for public drunkenness when Aamin Marritza was arrested. He was quite vocal in his displeasure at having to share his cell block with a Cardassian.
After Marritza was cleared of any charges and released, Kainon swelled with racism, took matters into his own hands and fatally stabbed him. His justification was "He's a Cardassian. That's reason enough!" He was then taken into custody by Odo. (DS9: "Duet")