Haruaki Azuma/Plot

Background
Azuma joined Border after it went public, approximately four years before Chika Amatori and Yūma Kuga enlisted. He was Border's first Sniper and together with the members of the first generation of Azuma Unit he climbed to the #1 position in A-rank. The members of the unit except for Azuma himself left it in unknown circumstances, to be replaced by Yukimaru Ichijō, Takaaki Katagiri and Karin Yuitsuka. Eventually, Azuma Unit reached its current composition, which in Noboru Koarai's case was due to him clinging to Azuma's leg for over an hour. Apart from his teammates, Azuma took on a great number of students in both strategy and sniping, such as Mirai Hatohara, Reiji Kizaki, Tōru Narasaka, Isami Tōma and Ren Tsukimi.

Introduction Arc
Azuma Unit was presumably involved in the extermination of all Rads in Mikado City.

Border Enlistment Arc
On the official Border enlistment day on January 8 Azuma is one of three Snipers, the others being Tetsuji Arafune and Ken Satori, serving as instructors to the new recruits. He is puzzled by Chika asking him if she has to run after shooting, to which he replies that she doesn't. The other trainees are amused by her enquiry, but, since that aspect of sniping is taught only to B-rank, Azuma infers that her mentor believes her to be capable of climbing up the ladder. After she inadvertently punches a hole in the base while trying out Ibis, he assures her that there is no problem and says that Satori, as the supervisor, will take the blame, which he reaffirms when she fears that he people at Tamakoma Branch will get in trouble on her account. When a furious Motokichi Kinuta barges in and starts venting on Satori, Azuma explains what transpired. Seeing him soften as he talks to Chika, Satori assumes that he has a soft spot for little girls, with Azuma remarking that she probably reminds him of his daughter. Concluding that Tamakoma Branch chose not to report her trion levels to enhance the shock, he assumes either Yūichi Jin or Takumi Rindō to be responsible.

Large-Scale Invasion Arc
Azuma Unit is deployed by Masafumi Shinoda to prevent the initial wave of Trion Warriors sent by Aftokrator from reaching Mikado City. Border's traps buy them enough time to arrive on the scene, which Azuma reports as he shoots down a Bado the successful suppression of the Trion Warriors. Just as Azuma Unit is about to go support other units after disposing of the Trion Warriors in the area, he notices a Rabbit emerging from a carcass and hears more Trion Warriors approaching. As soon as Tsuneyuki Okudera takes his eyes off the Rabbit, it attacks him and sends him crashing through multiple houses. Azuma warns Koarai to wait for their teammate before taking it on, but Koarai does not listen and is quickly immobilized by the Trion Warrior. Azuma attempts to shoot it, but the creature deflects his blast. Azuma then changes targets to Koarai, saving him from capture by forcing him to bail out. He then tells Shinoda about the Rabbit and its goal to capture agents.

Shinoda orders the other B-rank units to meet up with Azuma, and Taichi Betsuyaku reaches him moments before Lamvanein is warped right next to them. Azuma tells Betsuyaku to fall back and lure him into their range, taking note of the irregular Gate he came out of. Chano Unit attacks him, but before Azuma can warn them that Lamvanein is about to open fire, the Neighbor obliterates their trion bodies. Azuma and Betsuyaku run away, but, contrary to Azuma's expectations, Lamvanein rapid-fires at them, causing the Suzunari First Sniper to bail out. Arafune Unit attempts to snipe him, but he defends and his retaliation removes Yoshito Hanzaki and Atsushi Hokari from the battle. Azuma manages to get away, but even as more B-rank agents join him, they are still forced into hiding by Lamvenein's superior firepower, with Azuma wondering if the deadlock was what the enemy wanted to free up the Rabbits in the south.

When Kōhei Izumi, Shun Midorikawa and Yōsuke Yoneya join the fight, Azuma describes Lamvanein's Trigger. After Midorikawa cuts off his leg, Izumi lures the Neighbor towards Arafune and Azuma, who manage to shoot off pieces of Chelidon. Noticing that he now has less focus to spare, Azuma advises his allies to capitalize on their numerical advantage and pressure him until he shows an opening. This decision results in Lamvanein's eventual defeat, immediately after which he is rescued by Mira, whom Azuma identifies as a Black Trigger user. He instructs his allies not to give chase. B-rank agents are then assigned to defending the southern area, while the A-rank agents go help the trainees. Azuma thanks them and promises to treat them to a meal, a promise which he honors after the invasion is foiled. As a result of his actions, he is the recipient of an Outstanding Distinguished Service award as well as a Distinguished Service award as part of Azuma Unit.

B-Rank Rank Battles Arc
Azuma is invited as a commentator for Tamakoma Second's match against Arafune Unit and Suwa Unit. He is surprised by the map chosen by Tamakoma Second, as Cityscape C greatly favors Snipers. After the match begins, Azuma realizes that the selection was prompted by the unit wanting to form a natural alliance with Suwa Unit against Arafune Unit. He continues to analyze and describe the match and, after its conclusion, gives his overall commentary, focusing in particular on Tamakoma Second. When Shōhei Kodera explains to Futaba Kuroe just how decisive the unit's strategy was, Azuma light-heartedly comments that he has nothing to add.

On February 11 Azuma listens to Koarai and Okudera squabbling over the complexity of the map to pick against their opponents in the upcoming match. After prompting them to share their analysis and ideas in a coherent fashion, he voices his preference for a simple map before making sure they remember his tenets and exhorting them to create a winning strategy. Some time later, he authorizes Koarai to tweak the weather conditions. They eventually settle on Cityscape B with a snowy terrain.

On Saturday February 15, once the battle starts, Azuma spawns in the eastern area of the map, hidden with a white Bagworm. He spots Yūma and Sumiharu Inukai, and recognizes a third trion signature as Osamu Mikumo's from his movements. When Inukai engages Osamu, Azuma begins to move towards them. After two Attackers of Azuma Unit as well as Shinnosuke Tsuji converge into the building the battle has moved to, Azuma takes out the captain of Tamakoma Second by sniping through the walls. He moves away after the shot, and, when Chika opens fire, he rushes towards her, preventing her from bailing out on her own and taking note of her position for his teammates, although Kageura Unit allows her to flee. The Attackers of all four units begin a melee fight during which Azuma manages to shoot off Yūma's leg. He notices Yuzuru Ema bailing out and sees Hiro Kitazoe's Meteor shower, which he intercepts before targeting him directly. Masataka Ninomiya however shields Kitazoe before defeating him himself. Caught unawares, Azuma is unable to intercept the Gunner's final round of explosives. A few minutes later, only Azuma, Masato Kageura and Ninomiya survive. The Sniper is keen on running out the clock unless either opponent makes a move, and tells his teammates that the snow ended up working well for the map.

The following day, Azuma is invited by Shinoda to an emergency response meeting to address the possibility, mentioned by Enedrad, of an impeding attack from Galopoula or Rodochroun. When Jin states that he hasn't seen any agents or civilians being abducted or killed, Azuma speculates that the enemy is interested in something else, such as tech or intelligence. To the surprise of the agents present, Masamune Kido announces that the interception will be carried out confidentially. Azuma suggests enlisting Tsukihiko Amō's help, not to have him fight but to rely on his Side Effect. After the meeting he catches up with Kyōko Sawamura before asking Shūji Miwa if he's eating enough and inviting him out for a meal.