This came up in a topic in another forum. It got me to thinking about the other games a little more. So I wanted to throw this out there for the common folk.

How many important NPCs get killed from random events or normal encounters without you being anywhere close to the cell? Only to find a dead body lying there when doing a quest.

Two come to mind for me. The Master trainers of Destruction and Marksman. I have found them both dead before I ever met them. Thus leaving an uncompleted quest log. Are there any others that become quest breaking?