Ura Ex, extra short anime included in Blu-ray and the DVD releases of Ao no Exorcist.

Short prologue OVA, bundled with manga volume vol.10. Elsie receives from Dokurou Skull, hell's branch chief of "counter measures", the task to go on earth and capture evil spirits that have escaped from hell.

The brilliant Dr. Azuma created many robots to aid humankind. However, during a thunderstorm his lab was struck by lightning, corrupting the programming of one of his robots, BK-1, who renames himself Braiking Boss and declares that instead of serving mankind, mankind will now serve him! He brings other robots together into an overwhelming army bent on enslaving the human race. Tetsuya, Dr. Azuma's son, asks his father to turn him into an indestructible android so that he will have the power to destroy the threat his father inadvertently created. Shortly thereafter, Braiking Boss captures Dr. Azuma and his wife. Tetsuya, now renamed Casshern, sets out to turn the tide of the war and rescue his parents, with the help of his girlfriend, Luna, and robot dog, Friender.

A story of future Earth - A warning for mankind: In the future, our planet will be transformed into a strange new world where human life struggles on an Earth without rain or oceans - only vast, parched deserts. Two youths fight for survival on our hostile planet and find hope. The sea, the sky and the land had been completely polluted by mankind when mysterious objects fall from the heavens. These titanic vessels smash into the planet and suck up the air, water, and most living creatures into their womb, stealing away the very essence of Earth`s nature. The few remaining inhabitants struggle for survival against a hostile environment and an oppressive ruling race known as the Rodo. One young, hot-blooded human named Ran, fights against the Rodo and a world in which rain is only a legend. He strives to join an Anti-Rodo group known as the Hazzard, not only to defeat the Rodo, but also to hunt down the man who killed his mother.