Nationality would be the country a person was born in. Ethnicity would be their ethnic or racial background.
Example:
A person could be born in Canada and be Canadian but their ethnicity could be something like Chinese or African.
For ye shall hear, how our heavenly king
<span>Calleth Everyman to a general reckoning:</span>
The narrator is Strickland, as to his role: well it is his story.