Well there no point 8uilding it and then never using it. That doesn't mean that he 'needed' it. Recall also that he did seal it away in the Dark Temple. Again pointing to him not requiring it.
Originally posted by Mizukage Yoda
That the Emperor's technique is neither instant nor all powerful.
Lol. I never claimed that it was all-powerful. I provided a quote saying that none can stand in his presence and not succum8. As I recall, Revan did succum8. And also as I recall he developed a technique that ena8led him to resist Vitaites power. And was aided 8y the Exile.
Does the OP say that the Exile's ghost is helping Nihilus in this fight?