Not what I'm saying. There is a debate going on wondering whether it was the CoC that did, say, the SI quests, or someone else. Same with the guild quests, etc, etc, etc.
Basically, it just ends the CoC's story in a perfectly mysterious way. That's why I believe SI's main story was canonly completed by the CoC. Also, who else in Cyrodiil at that time would/could/should have survived that realm of Oblivion and who else would/could/should save Tamriel from Umaril and, in a sense, mantle Shezzar by taking Pelinal Whitestrake's place at that time? Such great feats, which were more fitting for a hero than just any powerful wizard or skilled warrior, unlike the guild quests, could have only been accomplished by a great hero, and I only saw once such hero helping Martin out and saving Tamriel from Dagon. The CoC lived on after the main quest was completed, would have likely investigated rumors of the end of the world(KotN), and would have likely investigated the strange door of the Niben Bay, which is another Oblivion gate(CoC specializes in dealing with these). Such a hero would disappear mysteriously as other Elder Scrolls heroes do and become Sheogorath, therefore staying in the Isles and out of Tamriel, where he/she would have once lived. It seems clear that Bethesda wanted us to believe that was the CoC's fate.