In 2369, Kainon was living on Deep Space 9 when he was detained for public drunkenness and placed into a holding area with the Cardassian Aamin Marritza. Kainon became quite vocal in his displeasure at having to share his cell block with a Cardassian.
After Marritza was released, Kainon, in his disdain for Cardassians, fatally stabbed Marritza declaring, "He's a Cardassian. That's reason enough!" Constable Odo then escorted Kainon back to his cell. (DS9: "Duet")