O'kar A'ko held the position of chieftain for the Ravagers, a well-known group of pirate criminals operating on the planet of Rishi. His reign occurred in the years leading up to the Galactic War fought between the Galactic Republic and the reconstituted Sith Empire. Widely recognized as a brutal oppressor, A'ko was overthrown in an almost bloodless revolt. This uprising was spearheaded by the Ravager Ruugar, a leader with great charisma, who then took A'ko's place as the captain of the group and remained in charge for a considerable period.
In the Codex entry dedicated to Ruugar within Shadow of Revan, the Digital Expansion released in 2014 for the 2011 video game Star Wars: The Old Republic developed by BioWare, O'kar A'ko's name was brought up.