The Talos Cult is a group of worshippers of the great Tiber Septim, founder of the Empire. In order to join, new recruits must swear the following oath: That we shall die to put a strong man back on the throne of Tamriel. They have many followers in the Legions, conspiring to assassinate whoever the current emperor may be and replace him, so to prevent the Empire's decline.
The Talos Cult only makes a small appearance in Morrowind during an Imperial Legion quest in Gnisis, where Darius asks you to uncover an assassination plot against the current emperor.
 Talos Cult Members