Those books have been such a pain... They destroyed Morrowind, killed Umbra. Ugh.
Well, Morrowind kinda had it coming through the Dumners own actions.. then there's what happened in TES III, which really led up to that in the end. The books pretty much describe what had been inevitable for a long time. Though the one thing I hated about the books were the typos I noticed.
Never used the sword myself though.. never had a use for it in Oblivion.