Blue Exorcist (2011) : 3x8

Michael Gedoin, lost in his admiration and adoration for Lucifer, takes further action to ensure the success of his Elixir research. He devises a plan separating Rin and his team – leaving each member to fend for themselves. Although Rin faces off against a giant, grotesque Zombie in the underground laboratory's container, he hesitates to use his sword against it when he realizes the Zombie is a human corpse possessed by a demon. Yukio, Suguro, Shiemi and Konekomaru each must face off against their demons in the laboratory alone...