Barugon

Introduced in the second film of the Gamera series, Barugon was Gamera's first-ever opponent. Though he never returned in a film outside of stock footage, he was featured in a manga adaptation of his debut film published by Kadokawa in 2002, which placed its events into the continuity of the Heisei trilogy, between Gamera 2: Attack of the Legion and Gamera 3: Revenge of Iris.