Bagan is an ancient super kaiju created by Toho that first appeared in the 1993 Godzilla game, Super Godzilla.
This kaiju has an infamous history in the Godzilla series, he was planned in several films through the 80's and 90's but kept getting scrapped.
Around the 50th Anniversary of Godzilla's appearance in Japan, the Millennians have finally made their arrival on Earth. Their plan is to release all the giant monsters so they'll wipe out entire cities in search of plasma and nuclear energy. Kiriko joins the Gotengo crew to awaken Godzilla one final time for Operation: Final War.
