Sacred Promise

Sacred Promise was a Covenant.

During an engagement with UNSC forces Sacred Promise was severely damaged ,forcing the weapons to be taken offline. An attempt was made to elicit support from Devotion and fighter cover from Commitment and Patience. However before any help could arrive, the ship crippled by a kinetic penetrator that disabled the engine control and put the main drive into 'runaway state'. The ship then began to accelerate uncontrollably into the thin atmosphere of a local moon. The crew was ordered to abandon ship as attempts were made to forcibly shut down the engines by ejecting the fuel cells. These attempts were unsuccessful.

Presumably Sacred Promise broke up shortly after entering the atmosphere.

Background
Sacred Promise was mentioned in the Transmissions as sending a message to the. It also made an appearance in Conversations from the Universe.