Border Enlistment Arc

The Rank Wars Arc is the Third arc of the series.

Characters

 * Yūma Kuga
 * Osamu Mikumo
 * Chika Amatori

Triggers

 * Scorpion
 * Eaglet
 * Ibis
 * Lightning
 * Ray-Gust
 * Asteroid
 * Chameleon

Attacker & Gunner Colossal Neighbor Simulation Battle
The first test for Gunners and Attackers was to defeat a Neighbor simulation within 5 minutes. Some of the strongest members in Border like Ai Kitora managed to do it in very little time. Osamu apparently couldn't defeat the Neighbor within the time limit. After a few rounds, it is Yūma's turn to fight. He goes up against the Neighbor and defeats it is 0.39 seconds! In disbelief, a participant asks him to do it again, which he complies to and defeats it again in even less time! Back with the gunners and attackers, Sōya Kazama approaches them, and it seems that he wants to fight Yūma. Jun explains that Yūma is still in C-Class, but Sōya stated that there was a misunderstanding and that he really wanted to fight Osamu.

Sniper Colossal Neighbor Simulation Battle
Meanwhile, Chika is with the sniper group, where they practice shooting a Colossal Neighbor with Border triggers. Haruaki Azuma notes that her mentor must have absolute faith in her, as she knew that snipers had to run. When she and another sniper are ordered to fire, she makes a big hole in the wall and apologizes. While apologizing for it, she is praised by her instructors and fellow snipers alike.

Osamu Mikumo vs. Sōya Kazama
Osamu accepted the Sōya's challenge. He brings out his trigger, but Sōya uses Chameleon to make himself invisible and then attack Osamu, effectively defeating him 20 times. Osamu asks him to battle him once more. With that, Osamu turns his Trion into small cubes and scatters them across the arena, effectively drawing out Sōya. He uses a Raygust to create a shield, and then uses a Thruster trigger to ram Sōya against the wall. He then uses Asteroid to turn his Trion into a sphere and hit Sōya with it. Sōya's sword impales Osamu's neck, rendering him down, but Sōya's left side is completely destroyed, rendering him down as well.