A mysterious boy from another world. Although physically small, he is experienced in combat, and his battle skills are extremely powerful. He has an honest personality and isn’t very familiar with Japanese customs. He has a special ability (Side Effect) that allows him to see through lies.

15 years old. He is a member of Border, an organization created to resist the Neighbors. He joined Border with a certain objective in mind. He has a strong sense of justice and faithfully performs his duties, but his combat and trion abilities are low. According to Yuma, he is very good at taking care of others.

13 years old. A childhood friend of Osamu’s. She seems timid at first, but she has a strong personality. The Neighbors constantly target her due to her powerful trion. Her brother and best friend were kidnapped by Neighbors.

An S-rank member of Border. 19 years old. He has a carefree personality, but his combat abilities are top-notch. Although he has an overconfident side and describes himself as a “Talented Elite,” he is also a dependable older brother figure and is trusted by others. He has the ability to predict the future.

Hyuse is one of the Neighbor. He attacked Mikado City in large-scale attacking and was confronted with Jin. Then he was discarded by Hyrein and left in this world. Currently, he is under Tamakoma Branch's control as a hostage of Border. After that, he joined Yuma's team on the condition that Tamakoma sent him to his mother country.

A five-year-old who is a resident of Border’s Tamakoma Branch. He’s Border’s secret weapon—their sleeping lion. He’s always with Raijinmaru. He has a special Side Effect ability that allows him to communicate with animals.

An Operator for Border’s Tamakoma Branch who concurrently serves Takakoma First and Second. She analyzes the Neighbors’ technology and supports the team in whatever way she can, both in and out of combat.

Captain of the B-rank Ikoma Unit. According to Jin, he’s the best Kogetsu Whirlwind user in Border. Of all the Attacker Triggers, his Kogetsu Whirlwind, called Ikoma Whirlwind, has the longest range, extending his attack by up to 40 meters. His teammates call him “Iko-san” and the nickname caught on.

A Shooter in the Ikoma Unit who also takes on the role of a military officer and gives orders to teammates that are being lazy. Unlike Ninomiya and the other Shooters, his combination attacks with Ikoma are very powerful. He often has humorous exchanges with Ikoma as if they were a comedy duo.

A mobile Sniper in the Ikoma Unit who uses the Grasshopper Trigger. Since he uses Grasshopper, he can reach the maximum number of Sniper points possible faster than other snipers, and if it comes to close-range combat, he can slip away from any opponent, even an Attacker.

A member of the Ikoma Unit. He has a tendency to rush into battle and often has blinders on—focusing too much on chasing the opponents right in front of him and forgetting to pay attention to everything else. He has a cheerful nature which leads him to be very carefree about everything. This frustrates Maori, the unit’s Operator, who is always reprimanding him about something.

An Operator in the Ikoma Unit. She is known among her teammates as “Mario.” She has a strong-minded personality and takes over the strategy room meetings whenever her teammates get off topic (which happens frequently). She repeatedly gives Kai warnings because he always does whatever he wants in rank battles.