Can someone tell me this book it has magic in it and evil spirits. This one evil spirit follows this guy around through his name.

Can someone tell me this book it has magic in it and evil spirits. This one evil spirit follows this guy around through his name. At the end the spirit is following him by his name and the book ends. I can't remember the name of it. I read it 20 years ago. When I was very young. I've been trying to find this book for years