Delta Quadrant species at war with the Kraylor, whose blockade of the Kraylor homeworld Harry Kim helped a Kraylor ship break during his first command.
The Annari are a spacefaring Delta Quadrant people locked in a long conflict with the Kraylor, enforcing a blockade around the Kraylor home planet with armed patrols. Their ships attacked a Kraylor vessel just as the Delta Flyer was passing.
In Nightingale, Harry Kim took command of that damaged Kraylor ship, believing it was carrying vaccines. Its crew were really scientists bringing cloaking research home to slip through the Annari blockade. Despite the deception, Kim kept his promise to the crew and got the ship past the Annari to the planet.