Which is the pronoun in the given sentence and what kind of pronoun it is -- He is a big fan of JKRowling?

The pronoun in the sentence is he.

The pronoun 'he' is a personalpronoun, a Word that takes the place of a singular noun (or name) for a specific male as the subject of a sentence or a clause.

EXAMPLE

with a noun: My brother is a big fan of JK Rowling.

with a name: Jason is a big fan of JK Rowling.

with the pronoun: He is a big fan of JK Rowling.