“If I am reading this correctly, there might be a way to use the power of Draenor to effectively purge a demon.
According to my father's notes, a place of snow and earth is required for the ritual. He will also need an untapped ley line to power the ritual.
There is a cave in northern Frostfire Ridge whose power might suffice. I will mark it on your map. Head north as soon as you can and I will join you there.”