Harbinger of Piety

The Harbinger of Piety was a Covenant CCS-Battlecruiser under the command of the Minister of Inquisition.

Background
It participated in the Battle of Earth as a part of the Covenant Loyalist Fleet and was subsequently destroyed by a MAC blast from the Nassau Station.

Battle of Cleveland
The ship had at least one San 'Shyuum; the Minister of Inquisition. The Prophet was curious about a Key of Osanalan, which was in fact, fake; it had been made up by James and Ruwan Ackerson when they were young.

Ruwan Ackerson had met the Covenant and told the Covenant that he was actually the key. Confused, the Covenant took the humans to the Harbinger. In reality, Ruwan had been implanted with a organic tracker for the UNSC to find and destroy high ranking Covenant officials.

Trivia

 * For unexplained reasons, the Harbinger of Piety is first depicted with four forward ventral prongs, as seen on CCS Battlecruisers in Halo 3. However, the picture of its destruction depicts it as only having two prongs like those in Halo: Combat Evolved.