During the attack by fire elementals on Nordrassil, the elemental Volcanus organises a ritual involving a bough of the world tree to destroy it. After he was defeated by a bold hero, the branch was recovered but now surged with both the power of life from Nordrassil and the fiery energies of the Firelands. When the hero returned to Kalecgos, the blue dragon fixed the Timeless Eye to the bough, transforming it into a highly effective staff.
Following the death of Tarecgosa at the hands of Arygos, her spirit is infused into the hero's body. After a vote of the blue dragons, Kalecgos is made the new Aspect of the blue dragonflight. He makes the hero and fallen dragon's bond stable, while granting further power to the bough, reforging it into the Runestaff of Nordrassil.
After using the Runestaff to siphon Smouldering Essences from the bosses in the Firelands and obtaining the Heart of Fire from Ragnaros himself, the blue dragons use these regents and their own powers to further empower the runestaff and fuse Tarecgosa's spirit into it, thus creating Dragonwrath.