Lieutenant Japar was an Klingon officer in the Klingon Defense Force who served as an engineer aboard a Bird-of-Prey.
Following the Klingon Empire's withdraw from Cardassian space, Japar's ship returned to Deep Space 9 where it underwent repairs. While at the station, Japar was taken to the infirmary with plasma burns. Miles O'Brien later tried to track down Japar because he was unable to "make head nor tail" of the power-relay systems on Japar's Bird-of-Prey. (DS9: "By Inferno's Light")