Board Thread:General Discussion/@comment-67.42.77.181-20150215034524/@comment-121511-20150215144843

It's because the Thalmor aim to destroy creation, and as many of The Towers have been destroyed, Talos is essentially holding Mundus together singlehandedly. It's also because Talos is the Patron God of Man, and the Thalmor also seek to completely erase the idea of mankind from the realm of possibility. While Talos exists, more or less, the Thalmor cannot achieve their goals.