The story is set in Diamond Ore Country, of which Diancie is the princess.This is a country located deep underground, where the Pokémon Carbink live together in peace. The energy source of this country is a giant diamond called the Sacred Diamond, which can only be created by princess Diancie. However, the current princess doesn't yet possess the power to create such a diamond, and the current Sacred Diamond's power is soon going to run out, which would result in the end of the country. Diancie meets up with Ash and Pikachu, and set off together with them to search for the legendary Pokemon Xerneas, which possesses sacred power, but on the way, they find the cocoon where the Destruction Pokémon, Yveltal, who was said to have once destroyed life in Kalos, lies in wait.

(Source: serebii.net)

Kujou-san no Do-S Soudanshitsu Anime-ban short anime specials bundled with the Blu-ray and DVD releases of Ore ga Ojousama Gakkou ni "Shomin Sample" Toshite Gets♥Sareta Ken.

A special shown at the Jump Super Anime Tour 2010. It was later released as an extra accompanying Nurarihyon no Mago Blu-ray Box 1.

In A.G. 101 (the 101st year of the Advanced Generation calendar) a mysterious entity known only as "UE", or "unknown enemy", attacks and destroys the space colony Angel. This brutal attack becomes infamous as the "The Day the Angel Fell", and marks the beginning of humanity's war for survival. The series begins in A.G. 108 when the UE attack the space colony Ovan, where Flit Asuno lives with his mother. Flit's mother is killed by the UE, and in her belongings (in an object called a "AGE Device") he discovers the blueprints for a powerful weapon from the past - the ancient messiah named "Gundam." From these blueprints, Flit spends the next several years studying engineering at an Earth Federation base on the Nora space colony and designing the AGE-1 Gundam. Seven years later, in A.G. 115, Flit completes the Gundam, just as the UE attack Nora. Flit and his lineage's battle piloting the AGE-1 to protect mankind is about to begin. (Source: GoodAnime.net)