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

Yako Katsuragi is an acclaimed high school detective, who, despite her young age, has solved many cases. In fact, there seems to be no case that she can't solve, or any culprit that escapes justice. But within the walls of her detective agency lies the secret to her prolific crime-solving skills: the cases are actually solved by her assistant, Neuro Nougami. However, to call Neuro an ordinary man would be incorrect. In reality, he is a demon, who came to the human world in search of the ultimate mystery, having already solved every mystery in the demon world. With Yako as his proxy, he feasts on the negative energy released by humans when they commit crimes. Thus, he promises to help Yako solve the mystery of her father's death. But to do so, he must avoid drawing too much attention to himself, which is why Yako plays the role of the detective. Majin Tantei Nougami Neuro follows this unlikely duo as they solve case after case to satisfy Neuro's ravenous appetite and Yako's desperate search for the truth of her father's death.

In the bustling and futuristic city of Heartland, a young boy named Yuuma Tsukumo has a dream that everyone his age wants to achieve—earning the title of the greatest duelist! Sadly, due to his lackluster dueling skills, this dream is far from achievable. But when the school bully, Ryouga "Shark" Kamishiro, splits the key given to him by his father into two pieces, he inadvertently sets Yuuma on a collision course with his dream. Retaining one half of the key, Yuuma begins a duel with Shark, but soon realizes that his inexperienced skills are no match for him. In a sudden turn of events, Yuuma's key repairs itself, and the "Door of Destiny'' appears before him. Using the key to open it, Yuuma is greeted by an alien by the name of Astral—a being only he can see. The bewildered Yuuma soon learns that his memories have been divided into 100 "Number Cards," all of which he must retrieve. However, he is also not the only one looking for them. Bombarded by these revelations, Yuuma, alongside Astral, must defend the world from the upcoming threats that loom over Heartland City—regardless of any divine intervention that may occur.

Short episodes with super-deformed characters posted on the official Twitter account. Includes three extra collaboration episodes with halca, the peggies, and eheya.