Kuniharu Kakizaki/Plot

Background
Kakizaki joined Border during its debut four years prior to Yūma Kuga's enlistment. He was at a press conference with his teammate at the time, Arashiyama, regarding Border's recruitment of new members. When asked by a journalist who opposed Border whether he would protect his family or fellow citizens if they could choose only one, Kakizaki was unable to anser, while Arashiyama did not hesitate to pick his family. Approximately two years later Arashiyama Unit was chosen as the PR unit, which prompted Kakizaki to leave it out of insecurity. Ayatsuji immediately introduced him to Madoka Ui so he could form his own unit, and he received applications from two prodigies, Kotarō Tomoe and Fumika Teruya.

Large-Scale Invasion Arc
Along with the rest of his unit, Kakizaki joins the fight against Lamvanein, initially failing to accept that the opponent could be as powerful as the reports suggested. When the Neighbor forces his enemies to hide, Kakizaki apologizes to the C-ranks for being unable to help them. At Azuma's command, the members of Kakizaki Unit start firing at Lamvanein to pressure him into revealing openings. The Neighbor targets Kakizaki, but he cannot aim properly while flying and Kakizaki escapes unharmed. Following Lamvanein's defeat, Kakizaki Unit is deployed to defend the southern area of the city. To the best of Tokieda's knowledge, it was the only B-rank unit to survive Aftokrator's invasion without a single bail out. It was also the recipient of an Excellent Distinguished Service award.

B-Rank Rank Battles Arc
Kakizaki comes across a lost Yūma and guides him to the place where the rank battles are held. When Yūma fails to recognize him, he reveals that his team is one of Tamakoma Second's upcoming opponents. He displays visible shock when Kako asks Yūma to join her unit, and again when he nonchalantly refuses. When Kako explains to Yūma that her goal is to recruit talented agents with the initial "K", he asks her if she has tried to recruit Kakizaki. She responds that he is not their type, with Kakizaki replying that she does not have to be considerate. He grows uncomfortable when Kako pretends to want to recruit Yūma by force and the two mock-fight in front of everyone until Kageura arrives, only for him to start pulling at Yūma too.

On the day of the match against Tamakoma Second and Katori Unit Kakizaki briefs his teammates about his map choice and their opponents' fighting styles. Ui enquires about his impression of Yūma, to which he replies that he seemed a nice guy, but he reassures Teruya that he will not hand the match to him, thinking that his unit should not be hanging around their current position in the ranking. He ultimately recommends the three of them stick together before spawning in. Kakizaki orders Teruya not to intervene when Yūma and Katori clash and the three teammates rendez-vous shortly after. Since they have no data on Tamakoma Second's new tactic, Kakizaki and Teruya flank Katori Unit while Tomoe breaks up their formation. They gain the upper hand until Tamakoma Second steps in, forcing them to fall back. Kakizaki Unit and Katori Unit both decide to fight each other and lure Tamakoma Second out of the wire zone, but just then Chika starts destroying buildings with Ibis.

Kakizaki lets Katori Unit swarm the spider nest first, since that makes it more likely that they will be targeted by Yūma; however, he is the one who comes to intercept them. Kakizaki prevents Tomoe from splitting off and going after Chika, thinking that all three of them will be needed to defeat Yūma and that Katori Unit should be able to get past Osamu. His arm is soon cut off by Yūma but they manage to drive him to an open area; however, Yūma stays close to Kakizaki, preventing Teruya and Tomoe from shooting at him, until they switch to their Attacker Triggers, at which point he steps away again. Kakizaki Unit starts cutting the wires, but they stop when Tomoe is sniped at with Lead Bullet and taken out by Yūma. Teruya offers to go after Chika by herself, and this time Kakizaki accepts. He creates an opening for her to slip past Yūma, continuing the fight against the ace on his own. Determined not to let down his teammates any longer, when Yūma stabs him in the chest, he holds him in place and fires at him from near point-blank range; however, Yūma manages to interpose a Shield and to survive while Kakizaki bails out.

After the end of the match Kakizaki apologizes to his teammates for being overly cautious and not letting them do as they suggested, but they object that nothing would have changed and urge him not to give up on their stable formation. Together they resolve to create two-to-one tactics to complement it, moving Kakizaki with their acceptance and initiative.