Days before the rebellion, the The Librarian had briefly visited Janjur Qom to collect specimens to protect them from the impending Flood attack. This visit sparked unrest among the San'Shyuum, who correctly surmised that the Librarian's visit could only mean that their lives were in jeopardy.
The San'Shyuum soon began a full rebellion, using a cache of hidden weapons and ships to make war on the Forerunners. A Forerunner fleet was permitted entry into the Quarantine Shield with full functionality and power, soon overwhelming the San'Shyuum defenses and taking control of the planet. A Halo ring was then unexpectedly brought in by 032 Mendicant Bias and used, presumably, to sterilize the planet.
The battle devastated the surface of Janjur Qom, destroying most of the planet.
During the battle, Didact's ship was interdicted and destroyed in orbit; as a result, Ur-Didact, Bornstellar-Makes-Eternal-Lasting, Chakas, and Morning Riser were captured by the Master Builder. Didact was said to have been executed shortly after the conclusion of the battle, though in actuality, he was intentionally placed on a Flood-controlled world..
- Halo: Cryptum (First appearance)