Pre-Series Timeline

List of events dated proior to the start of the series

9 years ago

 * Yūgo Kuga teaches Yūma "The 3 Teachings".
 * Kizaki's father is killed while protecting a child, allegedly by Neighbors.

5 years ago

 * 10 of the 19 Old Border members die in a Neighborhood conflict after trying to help their ally, Aristera which gets destoried and the remaining royalty flee to Earth.
 * Sōichi Mogami is one of the 10 who dies during this conflict. He uses his remaining Trion to create a Black Trigger.

4 years ago

 * Spinthir attacks Calvaria.
 * First Large-Scale Invasion
 * Motokichi Kinuta, Eizō Netsuki, and Katsumi Karasawa join border, presumably as executives.

3-4 years ago

 * Yūgo Kuga dies while saving Yūma.

2 years ago

 * Kazama offers Kikuchihara a place in Kazama Squad, to which he accepts.

1 year ago

 * Calvaria defeats Spinthir after years of war.
 * May 2nd, Rinji Amatori, Mirai Hatohara and other collaborators are confirmed to be missing after attempting to enter a gate to the Neighborhood.
 * Karasuma and Usami transfer to Tamakoma Branch for unknown reasons.

6 months ago

 * Arafune quits being an Attacker and becomes a Sniper.
 * Osamu enrolls in Border.

Start of Series
See: Timeline