After Marritza was released, Kainon, in his disdain for Cardassians, fatally stabbed Marritza declaring, "He's a Cardassian. That's reason enough!" ConstableOdo then escorted Kainon back to his cell. (DS9: "Duet")
Kainon was played by actor Tony Rizzoli in his only Star Trek appearance. His name comes from the script.
The script for "Duet" states the pronunciation of Kainon's name as "KAY-non" and goes on to describe him as, "an unkempt, even disheveled-appearing, mid-30's Bajoran" and a "thief/drunkard".