Two years ago prior to the start of the series, a group of young Burst Linkers reached level nine and were informed by the Brain Burst system about the harsh rules that needed to be fulfilled in order to reach level ten.They had a strong bond between each other hence, instead of fighting amongst themselves to attain level ten, the kings decided to make a peace treaty known as the non-aggression pact and each king claimed part of the land as their Legion territory. However, the Black King decided that instead of peace, they should fight to the fullest and attain level ten. When the other kings protested against her idea, the Black King beheaded the anti-war Red King, Red Rider on the pretext of embracing him and became the first and only known violator of the non-aggression pact.