- Main article: Rank
Oracle Master is an office of duty amidst the Covenant High Council; customarily, a Sangheili particularly knowledgeable in religious and political affairs is made the personal adviser of a Hierarch or a high-ranking military official. Oracle Masters also serve aboard ships, serving as data gatherers, advisors/mentors, and religious leaders.
It is known that an Oracle Master served as adviser to high-ranked officials including the Prophet of Regret, Imperial Admiral Xytan 'Jar Wattinree, and aboard other vessels in the Sangheilian Fleet.
The only known Oracle Master, Parala 'Ahrmonro, is described as old, but fiercely intelligent. Beyond that, little else is known about the rank, or the Sangheili who holds it.
- Halo: Ghosts of Onyx (First appearance)