Tsuneyuki Okudera/Plot

Background
Okudera joined Border approximately two years before Chika Amatori and Yūma Kuga, following his neighbor and crush Mako Hitomi's example.

Introduction Arc
Azuma Squad presumably takes part in the extermination of all Rads in Mikado City.

Large-Scale Invasion Arc
Azuma Unit is deployed by Masafumi Shinoda to prevent the initial wave of Trion Soldiers sent by Aftokrator from reaching Mikado City. Border's traps buy them enough time to arrive on the scene. Just as Azuma Unit is about to go support other units after disposing of the Trion Soldiers in the area, a Rabbit emerges from a carcass. Okudera briefly looks away to tell Haruaki Azuma to go deal with the approaching Trion Soldiers and at that moment the Rabbit attacks. Okudera blocks its punch, but the force of the impact sends him crashing through several houses. He is unable to return to the fight before Noboru Koarai is forced to bail out. Azuma and Okudera are able to escape the Rabbit, and Shinoda orders the other B-rank units to meet up with them.

When Lamvanein defeats Chano Unit, Taichi Betsuyaku, Atsushi Hokari and Yoshito Hanzaki, Okudera reports the losses to Tatsuya Kuruma and Kakizaki Unit. Despite their superior numbers, the Neighbor forces the surviving Border agents into hiding. Kōhei Izumi, Shun Midorikawa and Yōsuke Yoneya joining the fight prompts Azuma to order the B-rank agents to surround Lamvanein and keep pressuring him until he shows an opening. As the ranged fighters lure him into flying close to the ground, Midorikawa, Okudera, and Yoneya hide in a building close to one of them, ready to ambush the Neighbor as soon as he targets them. Lamvanein targets Kuruma and anticipates Yoneya's sneak attack, but the Gunner, Midorikawa, Okudera and Kotarō Tomoe combine their Shields, allowing the Attacker to get close enough to defeat the Neighbor. B-rank agents are then assigned to defending the southern area, while the A-rank agents go help the trainees.

After the end of the invasion, Azuma Unit becomes the recipient of an Excellent Distinguished Service award.

Round Two
Azuma Unit fights a four-way rank battle against Katori Unit, Ōji Unit and Yuba Unit in the day division on February 5.

Round Four
On February 11 Koarai and Okudera discuss whether they should tweak the map for their upcoming match, with Koarai insisting on it being their only way to stand up to higher-ranked units and Okudera protesting that luck is too big and unreliable a factor. Azuma asks them what they agree on, which is that they should prioritize close-quarters combat, although flaws in the plan quickly surface. Azuma voices his preference for a simple map and, after Koarai and Okudera propose watching Tamakoma Second's logs, makes sure they remember his tenet about fighting with strategy. Sometime later, Koarai floats the idea of tweaking the map again, which Azuma agrees to. They eventually settle on Cityscape B with a snowy terrain.

On Saturday February 15, Koarai and Okudera equip Grasshopper before the match and spawn in the south-east and north respectively. They activate Bagworm and quickly proceed to meet up. When Azuma tells them what enemies he sees, they decide to target Osamu Mikumo. Hitomi recommends they fight Yūma only with the three of them together. Koarai and Okudera launch a sneak attack on Sumiharu Inukai just as he is about to defeat Osamu, cutting off the Gunner's arm. Shinnosuke Tsuji arrives moments afterward, but the narrow hallway prevents Inukai from supporting him, giving the edge to Azuma Unit. After Azuma successfully snipes at Osamu, Chika forces herself to take a shot at the general location of the four combatants, but they survive. Azuma keeps the two Attackers updated on her position. The two members of Ninomiya Unit however reach her first, but to everyone's astonishment, Inukai is taken out by Yuzuru Ema and Masato Kageura before he can shoot her, allowing her to bail out on her own.

The Attackers of all four teams are now in the same place, and a battle royale begins. Koarai and Okudera engage Yūma in an airborne battle, focusing on him as he also has Grasshopper. After Tsuji breaks them up, Okudera warns Koarai about his proximity to Kageura, saving him by a hair's breadth. However, Hiro Kitazoe manages to fire off three rounds of Meteor before Masataka Ninomiya takes him out, wreaking havoc on the battlefield and pushing Okudera towards Kageura, who swiftly cuts him to shreds. Eventually, only Azuma, Kageura and Ninomiya are left, each hiding from the others. When Azuma tells Koarai that the weather setting worked out well, Okudera requests that he not encourage his smug teammate.

Round Five (Night)
On February 19, the night of Galopoula's blitz, Azuma Unit fights a rank battle against Kageura Unit and Yuba Unit.

Round Six
Azuma Unit fights against the Ninomiya Unit, Kageura Unit, and Suzunari First in the night division of the sixth round of rank battles. The team ties with Suzunari First while Kageura Unit and Ninomiya Unit lead with three points. No unit receives the survival bonus due to there being multiple survivors.

Round Seven
The members of the Azuma Unit then meet up to strategize ahead of their match against Tamakoma Second, Kageura Unit and Suzunari First. In the few minutes before the battle begins, Tamakoma Second is revealed to have added a new member, whom Koarai recognizes as Hyuse. Azuma exhorts his teammates not to lose heart but strategize. Okudera is nonplussed by Suzunari First's map of choice being Cityscape D. Koarai and he agree to equip Grasshopper. Despite his teammate's insistence on the contrary, Okudera feels that there is more to the stage chosen by Suzunari First than an anti-Sniper precaution. Azuma advises him to cherish his instinct. When Koarai suggests picking Hyuse off as soon as possible, Okudera reminds him of his crushing defeat at his hands, causing Koarai to concede that they should fight him as a team. The two respond correctly when Azuma asks them how they should fight a unit that outnumbers them.

Okudera spawns in the southern area of the map, which was given a nighttime setting, and tells Koarai to meet up at the eastern first-floor entrance of the mall. Azuma decides to enter the building as well. As he ventures into the mall, he activates his Bagworm to diffuse the Operators' attention. Out of sheer coincidence he runs into Osamu, who is also invisible to Radar, and proceeds to fight him. The Shooter manages to put some distance between the Attacker and himself by spreading his wires on the stairs. Koarai attempts to cut Osamu off on the fifth floor, and Okudera is surprised to see Osamu save his teammate from Ema's pick-off attempt, reckoning he must not want Kageura Unit to score. Okudera continues to give chase, resolute to take out Osamu before he climbs to the chaotic sixth floor, until the lights suddenly go off. As Ema shoots off Osamu's arm, guided by his Raygust's glow, Koarai and Okudera sheathe their Kogetsu. Osamu manages to get away as Okudera hides behind a corner, waiting for Koarai to return so they can catch Ema into a pincer. When his teammate is in position, Okudera tells him to wait until Ema gets off a shot. When he does, the two Attackers rapidly converge on him, with Okudera telling Koarai to use Senkū if Ema tries to jump to a lower floor. The Sniper breaks through the railing with the stock of his Ibis, narrowly avoiding their slashes; however, he is shot down by Azuma, towards whom Koarai and Okudera had lured him.

Shortly afterward, they see Osamu bailout. They close in on Hyuse and Yūma from the south while Azuma approaches from the north. The Sniper also has Hitomi activate the Dummy Beacons he planted earlier. In response, Chika fires an undivided Meteor cube at the mall. On top of destroying half of the decoys, the explosion causes Okudera to bail out and injures Koarai's foot. The defeated Attacker observes that Chika might have just become capable of shooting others. Azuma asks Okudera and him what their next move should be. Okudera starts off by saying that they should stay close to Tamakoma Second to avoid being caught in another blast, and then suggests full retreat, to which Koarai reluctantly agrees. Azuma manages to take out Hyuse, but Chika's ensuing bombardment leaves Koarai and him no choice but to withdraw, ending the match. Azuma states that both Attackers judged the state of the battle properly, and finally authorizes them to equip Sub Triggers, to their elation.

Round Eight
On March 5, Azuma Unit faces off against Kageura Unit and Ōji Unit in the day division of rank battles. During the match, which takes place in Exhibition Hall, Koarai and Okudera surprise the enemy teams by fighting with Gunner bullets for the first time. Okudera distracting Kageura with his bullets right before being taken out allows Azuma to pick off the rival captain. Azuma Unit wins the match with a final score of 4-3-3.