I'm not sure where this really belongs, as I don't know what it's really *spoiling* but I thought I'd throw it here to be safe.

While I was doing the Dark Brotherhood quests, killing a khajiit with Umbra, in a fort for the dead drops I heard a voice randomly tell me "Another one bites the dust, the khajiit is finished."

This actually startled me because it's never happened before. I was told that maybe a daedric quest could do it, but I don't actually have any daedric quests open besides the one for umbra since I have no intention of returning it. Any ideas on why that might have happened? Does umbra randomly talk?

Believe it or not, I have never convinced myself to even talk to Clavicus Vile, since I will not kill Umbra. When I have played a character who wants the sword, I take it from her without killing her (tricky but can be done).

So, here is what I can say for sure:

Umbra the sword is not Lilarcor and never ever talks.

I do not know enough about the Clavicus Vile quest to know if such remarks could come from his dog? Perhaps someone else could chime in to help.

Sorry I don't know that Daedric Quest well. There are several that I won't touch (Kill a unicorn? Make a paladin break his vow? No way. Lol).