First of all, I'm atheist - not religious at all. I had this dream back in 2009, but it felt significant at the time.
After a not-so-interesting scene in a supermarket, I entered a backdoor and found myself in what appeared to be Satan’s throne room. The room was a massive underground cavern (but I could see the sky through the cracks in the ceiling), and the throne was on a large rocky platform in the middle of subterranean lake of lava. Satan was sitting on his massive throne in front of me. He was large, unmoving, and wore a mask in the shape of a goat's skull.
A horde of demons appeared, skeletal dogs with big teeth. I had to fight them with my bare hands. They could do nothing but bite, and I could only fight back with my fists. I even ripped off one of the demon’s jaws. I felt intense pain of a kind I had never felt before in my back, and I hurt my hands badly by grabbing hold of that demon’s jaw and ripping it open. When they were all defeated, I moved forward to confront Satan himself.
He started taking of his masks (he was apparently wearing multiple masks to conceal his true identity) while a ghostly voice said “Revelations”. I also heard Gregorian singing in the background. I didn’t dare look because I feared to behold its horrible face. In fact, I couldn't look away. I tried, but He telekinetically forced me to watch. In the end I recognized the great evil… as myself. Actually, he looked like a combination of myself and my father in his younger years, but paler. I felt like it was a part of me, my future self. I asked a question about the masks. He told me how over time, he made those masks himself to protect himself. I felt this… sense of identification… it all felt so familiar. Then he said “You have a good heart, but you must be careful not to let anyone corrupt it. Beware the deceiver".