Except that Anub'arak hates Arthas, and is working against his own will.Originally Posted by Sunstria
Quote from Wowwiki:
It would appear that Anub'arak is yet another unwilling slave to the Lich King. Currently in Wrath of the Lich King, his quote upon death is, "Ahhh... RAAAAAGH! Never thought... I would be free of him..." This lends credence to what he said to Kel'Thuzad in Path to Damnation, when Kel'Thuzad remarked that in exchange for immortality he had agreed to give himself to the Scourge: "'Agreed' implies choice." retorted Anub'arak.