Blue Exorcist (2011)

Season 4: Episode 12

Yukio is arrested on suspicion of shooting Mephisto. After learning about Yukio's eye, Rin decides to escape from The Order with his brother. With the help of the Exwires and Amaimon, he heads off to rescue Yukio. Severely injured by the gunshot, Mephisto decides to abandon the barrier he placed on the artificial Gehenna Gate in order to maintain his possessed body. As a result, the gate opens completely, and a horde of demons emerge. The atmosphere of Gehenna thoroughly envelops Assiah...