Aterui

Avatar Aang, the world's last Airbender, learns of an ancient power that could save his culture from extinction. With the help of his friends, he embarks on a global quest to find it before it falls into the wrong hands and threatens to upend the peace they sacrificed everything to achieve.

In a mythical kingdom, the mighty Imperial Knights harness a magical substance known as Aer to power their weapons and protect humanity from the monsters of the forest. But something strange is afoot; the Aer is somehow changing, causing the wilderness to waste away and stirring the woodland beasts to attack with greater frequency. As danger creeps steadily closer to civilization, two young recruits - Flynn, the rigid son of a fallen hero, and the rebellious and brash Yuri - must ride with their fellow Imperial Knights to distant ruins in hopes of uncovering the truth behind the transforming Aer.

The "Academy Island Incident" in which four "kings" cross paths... Since then, Silver Clansmen Kuroh Yatogami and Neko have been searching for their master, Shiro. Without finding any clues to Shiro's whereabouts, the two became disheartened. However, one day, they see HOMRA members Rikio Kamamoto and Anna Kushina being chased by someone.

The wandering knight, Bedivere, reaches the end of his journey. It is A.D. 1273 in Jerusalem. The Holy Land has been transformed into a massive desert and its people have been forced out of their homes as three major powers wage war with each other in this wasteland. The Knights of the Round Table come together to protect the Holy City and their Lion King. With the whole of his kingdom summoned into a strange land, Ozymandias, the Sun King, quietly plots against the tyranny of this bizarre realm. The mountain people, protectors of those who were stripped of their land, await their chance at rebellion. In order to fulfill his mission, Bedivere heads for the Holy City where the Lion King rules. There he meets humanity’s final Master, Ritsuka Fujimaru, who has come to Jerusalem, accompanied by his Demi-Servant, Mash Kyrielight, in their quest to restore human history.