Who is The Reluctant Jew from Tevye the Dairyman and the Railroad Stories and what is their importance?

The reluctant Jew is a man who is clean-shaven and dressed like a Russian. He finally answers the nine Jews in Yiddish and tacitly consents to joining the Minyan. Later the mourning man jokes that the reluctant Jew can be a Jew, a non-Jew, and a pain in the neck.