Ryouma Echizen is one of 50 nationally ranked middle school tennis players to receive an invitation for the Japan U-17 tennis training camp. Previously open only to high school players, the exclusive regiment trains the best players in the country for the upcoming U-17 World Cup. The high schoolers are not pleased that these middle schoolers are allowed into the camp, but the middle schoolers easily overwhelm them before they are halted by the coaches. The rules of the camp are soon explained: the players are split into one of 16 courts based on skill, with the best players occupying Court 1. Players move up and down courts based on shuffle matches that occur before practice begins each day. In anticipation of a game, the middle schoolers are asked to pair up with one another, only to find out that they would not be playing doubles with their partners. Instead, they are pitted against each other in a tiebreaker-style game. The winner of the match would be allowed to stay to further develop their skills whereas the loser would be sent home. For the sake of tennis, friendships and camaraderie are all put on the line. As the fierce competition between the middle and high schoolers persists, the situations they find themselves in goes deeper than just playing to remain in the camp.

The first short story focuses on Favaro and Kaiser between the events of the first and second series as they visit Favaro's home village. The second short story shows Kaiser as a knight commander sparring with Jeanne, and sharing the reasons they remained as Orleans Knights in the aftermath of the final battle against Bahamut.

Thousands of years ago, the ancient dragon Bahamut wrought havoc upon the land of Mistarcia, a world where both gods and demons live amongst mankind. Working together to prevent the world's destruction, the rival deities barely managed to seal Bahamut, agreeing to split the key between them so that the dragon would remain eternally imprisoned. With the world safe from the destruction of Bahamut, it is business as usual for bounty hunters like Favaro Leone. Living a laid-back, self-serving lifestyle, the amoral Favaro goes about his work while on the run from fellow bounty hunter Kaisar Lidfard, a righteous man who swears vengeance upon Favaro. However, Favaro's carefree life is thrown into chaos when he meets Amira, a mysterious woman who holds half of the key to the world's fragile peace. Shingeki no Bahamut: Genesis tells the story of a group of unlikely heroes who find themselves caught in the middle of an epic clash between gods and demons, forced to carve their own path in the face of the imminent storm.