Xellus was a Sangheili city-state on Sanghelios, home to the 'Xellus clan. Its head keep was Xellus keep. In 852 BCE, Ussa 'Xellus warned the residents of the state to not trust the newly-formed Covenant or the San'Shyuum. The Covenant had learned of Ussa's heretical words and attack fighters were sent to destroy Xellus keep. After the keep was destroyed, the rest of the state was attacked by the Covenant military. The Covenant hoped that the attack would end the rebellion, but many of the state's residents survived and fled to the region of Nwari at Sanghelios' southern pole.
List of appearances
- Halo: Broken Circle (First appearance)
- Halo: Broken Circle, Chapter 1