In the novel American Gods by Neil Gaiman Shadow and Mr. Wednesday meet Czernobog. He tells the story of his use of a hammer as a "knocker", a job he has taken in America
"So, I got job on killing floor as a knocker. It was a good job. Yeah, skilled labor. A cow comes up the ramp. Boom, boom, boom. And you take a sledge hammer, and - Boop! You knock the cow dead. It takes strength. It takes strength, but not only strength. It takes talent, because it's a craft."
This character is aligned with the Slavic god Chernobog. Is there a connection in the mythology between Chernobog and a hammer or was the merely a creation of the author?