We didn't know this at the time, but "Demon" is a dog owned by one of the ski employees at the ski area on Volcan Osorno. He was standing outside our accomodation in the morning, tail wagging, and very friendly. He appeared again as we were putting our skis on to skin up. Despite trying to tell him to go down, he just followed/led us up the hill. The only reason the dog turned back is that a local who was also heading for the summit, decided to head down about 250m below the top, encouraging Demon to go with him. Apparently, Demon has been to the top many times, and happily guides people in exchange for a few snacks...