Orastrasz was a red dragon charged with guarding the Dragon Soul in a hidden location guarded by wards and buried deep beneath the Redridge Mountains. Deathwing, who intended for the Orcish Horde to gain control of the Dragon Soul, subtly coaxed Zuluhed the Whacked and his Dragonmaw clan to Orastrasz' location, at which point the orcs immediately fell upon the guardian. They had never faced a red dragon in battle before, and over a dozen orcs perished before they succeeded in killing Orastrasz.
Zuluhed ordered the Dragonmaw's greatest warlock, Nekros Skullcrusher, to recover the artifact. The orc shattered the relic's defenses and renamed it the "Demon Soul" due to the faint fel energies lingering on it from the time of the War of the Ancients. Far from Redridge, the Dragonqueen Alexstrasza sensed the breaking of the artifact's wards, and when she heard no word from Orastrasz, she took several of her red dragons and hurried south in the belief that some foolish mortal had somehow stolen the Dragon Soul, and that Orastrasz was in the midst of trying to hunt it. They believed that it would be easy to help him retrieve it, but in truth they were flying into Deathwing's trap.