I think the key is, narcissistic people are incapable of wanting to see their own darkness, thus, they are never the villain in any one else's story.

Which means integration of self is almost impossible for them without deep therapeutic work, if that's something they can even bring themselves to admit they need.

Lastly, as a rule, if someone says they are never a villain in someone else's story, chances are they are, they just vehemently seek not to know it.