Kryubi was an ornithopter pilot who transported Baron Vladimir Harkonnen around a spice factory. Initially Kryubi was nervous and uncomfortable at having such an important and volatile passenger in his care. During that time, they were witnesses of a spice blow. Kryubi managed to hold the 'thopter steady and saved both their lives.
He was taken to Giedi Prime and became Burseg, head of Harkonnen house security. He and his regiment received the second Bene Gesserit delegation when Gaius Helen Mohiam came for a second intercourse with the Baron, and insisted that only her should meet him, without her acolytes and guards.
He was in charge of the convoy kidnapping prisoners that came to Gurney Halleck's village that took Halleck's sister.