So, there are three ways out of the Sanctuary, and they're all through the doorways that this cacodemon knew as Epsilon, Delta, and Theta. Delta leads to the Warrens, and beyond that is the Abyss. He didn't know much about the Abyss, except that it's the darkest place in Hell. Epsilon leads, after a few Fortresses, whatever those are, to the Fields of Asphodel, like the Greek myth. Actually, there are a lot of Greek references here... Strange. That's probably where Murph and Radegast are. As for Theta, he didn't know much about Theta except that it contains the Throne room. Lethal would know more about that then the demons would. Also, we know that the demons are loyal to the Overmind, which links them all together, and learns about our strengths and weaknesses. It in turn serves the King or Queen, and I also believe that the Overmind is located in the Abyss. That's all we were able to glean from this creature. Let's use this against them.