Whether you are a longtime fan of ISSTH or still in the middle of reading it, you will probably benefit from this video on the subject Immortal, God, Demon, Devil, Ghost: Definitions, Similarities, Differences. 

I discuss the topic of these five Chinese characters, and why I translate them the way I do. There are no spoilers in here about ISSTH or any other novel, this is purely informational about the Chinese language aspects.

Check out the video here!