Narcissism is basically self-love. Something most healthy people have to a much lesser degree than Trump. The general definition of Narcissist is:
nar·cis·sist
/ˈnärsəsəst/
noun
a person who has an excessive interest in or admiration of themselves.
"narcissists who think the world revolves around them"
Clearly Sky and that troll think the world revolves around them. So do Trump's supporters.
Narcissist Personality Disorder is a clinical diagnosis and, yes, about 1% of population fit the characteristics listed for NPD.
It is quite possible that both sky and that troll are NPD, perhaps not yet diagnosed, perhaps they have been.