Here's the WC3 manual bit, yeah maybe I'm misremembering:
Just as Ner’zhul and his followers entered the Twisting Nether – the ethereal plane that connects all of the worlds scattered throughout the Great Dark Beyond – they were ambushed by Kil’jaeden and his demonic minions. Kil’jaeden, who had sworn to take vengeance on Ner’zhul for his prideful defiance, tortured the old shaman mercilessly by slowly tearing his body apart piece by piece. Kil’jaeden kept the shaman’s spirit alive and intact – leaving Ner’zhul painfully aware of his body’s gross dismemberment. Though Ner’zhul pleaded with the demon to release his spirit and grant him death, the demon grimly replied that the Blood Pact they had made long ago was still binding – and that he would make use of his wayward pawn once again.
Still, there's always Bridenbrad to consider.