The Mannoroth blood oath enslaves much of the Horde

Full History

The orcish clans were not born as a single army. Their leaders commanded separate peoples on Draenor, and many of their traditions were bound to shamanism and the spirits of their ancestors. The Burning Legion sought to change this society into a conquering force that could serve demonic designs. Kil’jaeden’s manipulation of Ner’zhul began that transformation; Gul’dan’s growing mastery of forbidden magic carried it further. By the time the clans were drawn toward a common war, the authority of their chiefs was already being redirected toward ends they had not freely chosen.

The blood of Mannoroth offered a terrible shortcut to strength. At Gul’dan’s urging, many chieftains accepted it, believing or hoping that the power it conferred would serve their ambitions. In the original Warcraft account, the rite deepened the Legion’s hold over the Horde and sharpened the bloodlust that would accompany its campaigns. This was more than the corruption of a few warriors: clan leadership itself was implicated. Those who joined the ritual helped commit their followers to a war whose true masters were demons.

The refusal of Durotan is therefore a necessary part of the story. The Frostwolf chieftain would not take part in the blood oath. His defiance did not prevent the greater Horde from being transformed, and it placed his clan apart from the direction set by the dominant chiefs and Gul’dan’s Shadow Council. Orcish resistance to the Legion existed from within the people even while much of their leadership accepted its gifts. The difference would matter long after the first clans had passed through the Dark Portal.

With demonic power came conquest and destruction, first on Draenor and then in the human kingdom of Azeroth. The curse also became a burden carried by descendants who had not themselves taken the first oath. When Grom Hellscream later drank Mannoroth’s blood again in Ashenvale, the old dependence reasserted itself. His final killing of Mannoroth, at the cost of his life, broke that binding. The original oath thus belongs at the center of both the Horde’s fall into corruption and the painful effort to reclaim its freedom.