I was looking at those little cores that the Phantom Wolves dropped, I felt they were very different from the monster cores I normally see.
"Monster cores normally have a slight warm energy inside them, but undead monster cores release cooler energy, that's because monster cores have a trail of vital energy left over from the monster that just died, but the Undead- living are already dead from the beginning." (Hela)
"You know a lot about the undead, Hela." (I)
"I have the memories of my previous life as Farus, he learned a lot about Undead from the Heretic God Kaharak." (Hela)
"Learning directly from a God whose authority of power lies in death would make Farus a genius Necromancer, that would be an opportunity any Necromancer kills for." (Ragnar)
"He was an idiot, he let himself be manipulated knowing he was just a tool for that Heretic God." (Hela)