From Halopedia, the Halo wiki
Druss was a Jiralhanae serving in the Covenant attached to the Covenant cruiser, Rapid Conversion in 2525. He was a part of Maccabeus' pack. He had not earned the masculine "-us" suffix, which is given when a Jiralhanae reaches adulthood.
Battle of Harvest
After recovering the Deacon Dadab and the Huragok Lighter Than Some, the crew of the Rapid Conversion discovered the human agricultural colony of Harvest in the Epsilon Indi system. Maccabeus' assessment of the planet with the ship's Luminary showed thousands of relics, but the devout Chieftain was soon shocked to learn that Dadab believed that there was an "Oracle" located on the planet. After a violent encounter with the Kig-Yar of the missionary ship Minor Transgression, the humans on Harvest sent the crew of Rapid Conversion a message, detailing that humans wanted peace and wished to give the aliens a peace offering.
List of appearances