When the war against the draenei was over, Blackhand accepted Guldans argument that a new world was needed for the Horde to conquer, as Draenor was dying from the warlock magics that were now practiced so freely throughout the Horde. He led his troops through the Dark Portal, and there he began to see his unimpeded path to power and prestige balked for the first time. First the army of the humans balked his Horde at every step, then his own daughter Griselda, tired of her fathers patronizing attitude towards woman proved herself beyond his control. Her alliance with the ogre Turok and her fortification of the Deadmines was seen as an affront by her father, and he ordered her death. Considering hed forced her to undergo the Drain Life ritual to age her to adulthood, then forbade her to drink the blood of Mannoroth in order to shame her, its not surprising she rebelled. Her death seemed to teach Rend and Maim, his two sons, better obedience. Its unknown if Griseldas death in any way spurred Orgrim on – he was known to have liked Griselda alone of Blackhands three children.
What is certain is that, tactically brilliant though he was, Blackhand was too much Guldans puppet to lead the Horde to successful victory over the humans. This is because Guldan didnt actually care if he won or lost against the humans. It was a divine apotheosis that Guldan pursued on Azeroth, in a partnership with the human wizard Medivh (who was himself host of the spirit of Sargeras) and so, while Blackhands Horde floundered attempting to destroy Stormwind it was only a matter of time before Blackhand himself was on the chopping block.
Interestingly enough, Blackhand was still successful in his plan. He and Guldan managed to insert Garona into the Kingdom of Stormwind, where she struck as the assassin she was bred to be, cutting out King Llane Wrynns heart and thus dooming Stormwind to defeat. Yet while Blackhand was on the verge of triumph, his ally (and secret master) Guldan found himself comatose following an attempt to wrench the location of the Tomb of Sargeras from the dying mind of Medivh. While Guldan lay trapped in his own body, Orgrim Doomhammer killed Blackhand the Destroyer, who never saw it coming. Able to play the role of general and plan the most outrageous of betrayals, Blackhand seemed incapable of believing anyone who said good things about him could ever be a threat, and he died for it.
The aftermath of Blackhands death was fascinating. Doomhammer (known as the Backstabber by those loyal to Blackhand) became Warchief, his first action to dismantle the Sythegore Arm to prevent those loyalists from moving against him. Of his fateful decision to allow Guldan to live, weve already spoken – but he also allowed Rend and Maim Blackhand and their Black Tooth Grin clan to exist, and serve the Horde, a mistake that would gall Thrall later on. In the end, Blackhands genius for planning and executing plans couldnt save him from his weakness, his need to believe that he was far more respected and capable than he actually was.
As for his Iron Horde http://www.wowtoes.com/ counterpart, he never found himself a Warchief. Perhaps this helped him control his raging egomania, or perhaps the ruler of Gorgrond is as prone to flattery as the Warchief was. Well find out soon.