I had 5 Louis Letrushes that were all immortal. Then, randomly on some road, a mercenary was talking to a Louis Letrush and killed him after a short argument. I went back to Whiterun stables (where the Letrushes were congregating), and was then able to kill the other 4.
I had 5 Louis Letrushes that were all immortal. Then, randomly on some road, a mercenary was talking to a Louis Letrush and killed him after a short argument. I went back to Whiterun stables (where the Letrushes were congregating), and was then able to kill the other 4.