What is the Blood-Oath of Draupnir in the Destiny Cycle?

The Blood-Oath of Draupnir is a binding covenant sworn between Breanna Ban Morna and Odin upon the sacred oath-ring Draupnir. Breanna swears the oath to Odin in Valaskjálf, committing herself to prevent Loki from becoming the spark that ignites Ragnarök.