Large-Scale Invasion Arc

The Large-Scale Invasion Arc is the 4th arc of the series.

Trion Soldiers
Trion Soldiers look like animals and insects that are fused together. They are made by the Neighbors and are used during war or for capturing people who have a high Trion ability. They usually have an "eye" in their mouths.

Triggers
Triggers are weapons made by Neighbors. Border also uses them to fight against Trion Soldiers because that is the only way you can defeat Neighbors. If you activate a Trigger, your real body will be stored inside the Trigger and you will have a body made of Trion.

A New Model
The invasion begins with Trion Warriors killing all the border agents in the city. In the school, Osamu instructs the students to evacuate with the teachers, and Chika and Natsume to help the evacuation. Yūma accompanies him to fight the Trion Warriors. Due to the Warriors having an outwards direction in attack, Shinoda splits the units, and sends Jin and Amō to the northwest. Traps are used to delay the Warriors until Suwa Unit and Kuruma Unit arrive. Azuma Unit and Kuruma Unit both encounter a new Trion Warrior.

The new model proves to be overwhelming, as it constantly counters all attacks against it. It manages to overwhelm Azuma Unit, forcing Koarai to Bail Out. With the intel from Azuma, Replica determines it's a Rabbit, a new model being developed in Aftokrator. It's so powerful that a lone A-Class agent would not be able to defeat it. The Rabbit's purpose is to capture Trigger users. Aside from it's already-powerful abiltiies, it cubifies Suwa. Kazama Unit takes over.

While discussing the possibility of the Rabbit being overwhelmingly powerful with Kido, Shinoda declares that he may step in.

Kazama Unit fights the Rabbit, albeit with difficulty. After receiving a hit from it, Kikuchihara manages to determine the strongest and weakest spots. Meanwhile, humanoid Neighbors begin to watch Border's battle with the Rabbits. They discuss the power, the captain, Hairein asserts that "Miden" still didn't show its full ability. Meanwhile, Osamu continues to fight many Trion Warriors, only to be overwhelmed by the sheer number. Replica explains that the elimination of the Warriors would take place one-by-one, endangering the evacuations like with Chika. Before Osamu can take action about it, a Rabbit confronts him. However, Yūma uses his Black Trigger to destroy the new model, despite the implications. However, Chano Unit attacks him, believing him to be a hostile Neighbor. The Rabbit, having not been destroyed, attack Chano, however, Arashiyama Unit saves her. At that point, Trion Warriors attack the HQ, only for Tachikawa to attack them. Osamu asks Shinoda for permission to assist Chika and the other C-Class members. Kido authorizes Osamu's doing so, but not Yūma's, as he may be mistaken for the enemy. Kitora accompanies Osamu.

Reaching the scene, they encounter a Mod Rabbit and a Mole Mod. Osamu battles the Mole Mod, defeating it, and Kitora battles the Rabbit. The Mod Rabbit overwhelms her at first, forcing her to dismember her leg to defeat it. From its body, three Rads come out, and summon three other Mod Rabbits. One cubifies Kitora. The rest attack Osamu and the other C-Class agents, but they are saved by Tamakoma First, Border's strongest unit. Tamakoma First easily takes out the Trion Soldiers sent to capture Chika, but the humanoid Neighbors join the battle.

B-Class United Teams & New 3 Idiots vs. Lamvanein
Lamvanein encounters the B-Class union near the Old Mikado City University and attacks them. Using his Trigger Chelidon, he easily overwhelms them, taking out Chano Unit entirely, and wiping out members of different units. As things become bleak for them, Lamvanein prepares to go support Hus and Visa. However, Midorikawa, Izumi, and Yoneya counterattack him. With information from Kunichika, they manage to get him into a tight space. He does eventually manage to trap Midorikawa inside the building. Midorikawa quickly slashes a fire extinguisher and uses the gas as a smokescreen. He then cuts off Lamvanein's leg, forcing him to be in constant flight. Using the flight to his advantage, he rains down bullets on the teams, injuring quite a few. He decides to take them down one-by-one, and has Kuruma as his first target. While flying towards Kuruma, Yoneya jumps down, attempting to ambush him. However, Lamvanein turns over, and shoots at Yoneya. Midorikawa, Yoneya, Teruya, and Kakizaki combine their shields to protect him, and he proceeds to stab Lamvanein. Lamvanein reverts to his normal body, and is retrieved by Moira.