Why do the diagnostic features of narcissistic personality disorder fall on a spectrum?

Then choose a historical figure or a character from TV or a movie to answer the following questions:

In what way does this person exhibit grandiosity and self-importance?

Based on the article, which of the narcissism types most accurately reflects the character of this person?

What are the various cognitive, emotional, and environmental causes of narcissistic personality disorders?

Why do the diagnostic features of narcissistic personality disorder fall on a spectrum?

How does the concept of personality disorders apply to any of the following programmatic themes? You may want to review the Programmatic Themes document.
Self-care
Social justice
Emotional intelligence
Career connections
Ethics