It was Dietrich Eckart, an occultist, alcoholic and a drug addict.
Eckardt told Hitler that he was on a mission to prepare the vessel of the Antichrist, the man who would be inspired by Lucifer to conquer the world and lead the Aryan race to pride and glory. Hitler thought he was that man.
It was from his studies of occult practitioners that Eckardt devised the rituals he used when he “opened the centers of Adolf Hitler to give him a vision of and a means of communication with the Powers”. Having done his worst, Eckardt eventually died, proudly advising those around him to follow Hitler, with these words: “Our father, Adolf who art on earth Hallowed be thy name, The Third Reich come ...”
Hitler had put himself in the place of God and wanted people to worship him.
Hitler's subsequent rejection of Freemasons and esoteric movements doesn’t necessarily mean otherwise. Occult circles have long been known for cover-ups and espionage.
I was looking into Hitler being possessed. Source on Eckart was mostly this: http://www.illuminati-news.com/hitler-occult.htm
But also on Hitler this: https://mgr.org/hitlerwaspossesed.html
And this: https://www.ncregister.com/news/vatican-exorcist-hitler-knew-the-devil