About the divination card: The Immortal

Hello,
I have collected data and did research to assume that The Immortal only drops from the grandmaster Dy'Ness. Other players have the opinion it can drop from any exile in the hall of grandmasters map. I had this kind of discussion ~2 years ago and today once again.I can't seem to find an answer. I really want to know. Every time this is a topic it always end up with no definite answer.
If you can could you please help me with this?
Thanks

I can confirm after doing ~500 HoGM's, and 5 immortal cards later, that I ONLY see them drop from DyNess.