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

Satoshi and his friends get lost in an unknown wasteland. They eventually come across a "Water Pokemon Show" performed by the star of the Mariner Troupe, Hiromi. Hiromi is a descendant of the troupe of Water People able to communicate with water pokemon, and she tells our heroes the legend that's been passed down by her people for generations. According to legend, a temple the Water People built called "The Water Temple Akuusha" rests somewhere in the ocean, and a treasure called "The Water Crown" is hidden there. It's said that no one has ever seen this treasure, but that changes when a Pokemon Ranger named Jack Walker (aka Jackie) appears to chase aftert it.

Jackie is on a top secret mission that has him protecting the egg of the leader of the water pokemon, Manaphy. This pokemon, called the "Prince of the Sea," needs to be taken to the Water Temple Akuusha, so Satoshi-tachi and Hiromi decide to help him. Along the way, a pirate named Phantom attacks our heroes from his great submarine. Phantom plans to use the Water Crown's power to help him conquer the world, but he'll have to solve the mystery of Manaphy's egg first. When the Rocket-Dan get into the mix, Jackie uses his Capture Styler to borrow the power of a nearby pokemon to stand up to them. Satoshi and Pikachu enter the fray, but they still have to contend with the attacks of Phantom's powerful high tech mecha! Suddenly, the egg starts to shine with a vivid light, and Manpahy is born! 

What is the mystery of the legendary treasure? What mysterious powers does Manaphy have? Can Satoshi-tachi and Jackie complete their top secret mission? The journey to reach the Water Temple Akuusha has begun!

Haneda Takashi has a secret he cannot speak of. To leave his dull school-life, he was supposed to have escaped to another world. However, he is reeled in by certain ties on his heart. One of these is Kobato, his awkward younger sister. The other is Watarai Asuka, his negligent girlfriend. Chitose Shuusuke is a poor freeloader. He passes his days working at various part-time jobs. One day, he has a disastrous first encounter with Tamaizumi Hiyoko. The next time they meet, Shuusuke discovers that they are fellow employees at his part-time job. Narita Hayato sees himself as a "hard-boiled" person. Back-breaking jobs are nothing to him. Hayato shuns normal human contact, but, during the nights, he would get together with delinquents and other denizens of the night. One such night, he meets the cheerful and oblivious Otori Naru. The relationships with these girls will greatly affect these 3 young men. But what, exactly, is the relationship these young men have with each other? (Source: AnimeNFO)

Shinkurou Kurenai is a 16-year-old student by day and a dispute mediator by night. Though kind-hearted and patient, due to his tragic past, he has trained for years to live on. Now, despite his unimposing appearance, he is a strong martial artist, who also possesses a strange power. While taking various jobs for his employer, Benika Juuzawa, one assignment leads Shinkurou to live with Murasaki Kuhouin as her bodyguard. Murasaki is the seven-year-old daughter of a plutocratic family, who escaped her home under peculiar circumstances with Benika's help. Commoner life, in her eyes, seems bizarre. However, by interacting with her neighbors, she grows more accustomed to the daily routine, and rids herself of her snobbish behavior, gradually growing attached to Shinkurou. Though many details of the job remain unclear, Shinkurou still strives to protect the young lady. But to make things more complicated, he also lacks a crucial fact—what is the real threat against Murasaki? [Written by MAL Rewrite]