Avatar: The Last Airbender / The Legend of Korra - After That Purging Line And Concentration Camp Allusion, It Too Hard Not To Notice.

They seem to be alternating Leftist and Rightist villains each season: Amon was a Marxist, Unalaq was a religious fundamentalist, Zaheer's an Anarchist and Kuvira's a Nazi. Ozai fits the pattern, since he was an old-fashioned Imperialist like Nicholas II, Leopold II or Wilhelm II.

The Fire Nations were more Empire Japan with a dash of Nazi Germany.