This has probably been brought up many times, but when the player meets Sheogorath, he makes several references to Oblivion questlines. The main quest, the Thieve's Guild, SI, and the Dark Brotherhood. The reference to the DB is, of course, a severed head. The severed head isn't encountered until near the end of that specific questline. Does anybody else think that this indicates that the COC was, at one point, in the DB?