I fought against VoN and after about 5 minutes he was near dead. Then he became invisible and I couldn`t target him anymore. While he`s invisible, he spams spells and summons ghosts like crazy, and he doesn`t become visible again, after more than half an hour I finally ragequited!
How am i supposed to kill him, when he stays invisible for half an hour?
Please, help!!!

I'm fairly certain this is a bug.
I killed him in two of my playthroughs (Disfavored and Anarchist) and never encountered this issue.
Which path did you choose?

Which faction did you ally with? Disfavored? Scarlet Chorus? Rebels? None of the above?

Well, really allied? Hm, I worked together with Graven Ashe, but I was not part of his army.

by gittin gud

Okay, I found out, that it was a bug.It seems, as if the german version is bugged. After switching to the english language, Voices of Nerat didn`t disappear anymore, so I was able to kill him.