I believe these two scenes are from a Conan story, although I'm not sure — it's been sixty years since I read it. The first scene is early in the story. Conan is with a woman who betrays him somehow. When he finds out, she is afraid he is going to kill her, but he only throws her out the window into a dung heap. Somewhere in the course of the story he encounters a man who wears a Mongol-like pigtail; I can't remember if he was an ally or an enemy. The two lose contact; shortly afterward Conan finds himself in a dark, abandoned city or castle that is filled with supernatural evil. He sees the Mongol from a distance; approaching, he discovers the man has been decapitated and his head is suspended by the pigtail.