The fact that the area is called "Uvirith's Grave" should be e bit of a giveaway as to why the owner of the new tower has a different name.
It would be nice to know what happened to Uvirith though, who she or he was, and what they did that was so terrible that they were buried in an otherwise unmarked grave in the middle of nowhere. Is there a book in the game that sheds any light on him/her? If not maybe ML can put his imagination to work and place a tome in the tower.