Pre-Series Timeline


 * Rinji Amatori is born.


 * Jin Yūichi is born.
 * Jun Arashiyama is born.


 * Isami Tōma is born.


 * Osamu Mikumo is born.
 * Yūma Kuga is born.


 * Chika Amatori is born.


 * Yotaro Rindō is born.


 * Neighbors attack Mikado City and Border agents defend against them.
 * Yūgo Kuga dies while saving Yūma.


 * Yūma comes to Mikado City from his world.