User blog comment:EmpyreanSmoke/Supernatural Q&A/@comment-3045936-20150930094023/@comment-24834479-20150930181024

1. It effected them most likely, so it didn't really leave them alone.

2. I would assume it would have differences than a deceased human body.

3. I assume there has been battles in the past.

4. He knew that once he killed that he would go crazy, so he told Dean he needed to o be killed ahead of time.

5. Maybe.... ;)