Shinnosuke Tsuji/Plot

Background
Tsuji enlisted in Border approximately three years before Chika Amatori and Yūma Kuga. He eventually joined Ninomiya Squad, rising to A-rank and at one point passing the selection for the Away Team; however, Mirai Hatohara's inability to shoot others caused first her, then the whole squad to be removed from the force. On May 1, the team dined together at a barbecue restaurant to celebrate Sumiharu Inukai's birthday; shortly afterwards, Hatohara ventured into the Neighborhood with her accomplices, causing Ninomiya Squad to be demoted to B-rank as punishment.

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

Large-Scale Invasion Arc
Due to Masafumi Shinoda preventing B-rank Squads with missing members from fighting against Aftokrator's forces out of fear of capture, Ninomiya Squad is not deployed.

B-Rank Wars Arc
Ninomiya Squad fights the first round of Rank Wars on February 1.

Round Two
Since Azuma Squad, Katori Squad, Ōji Squad and Yuba Squad compete in a four-way rank wars in the day division on February 5, and Ninomiya Squad is known to have clashed with Ikoma Squad on that same day, the battle presumably took place in the night division, with Kageura Squad as the third team.

Round Three
On Saturday February 8, Ninomiya Squad competes in the third round of rank wars.

Round Four
On February 15, during the night division of rank wars, the match between Kageura Squad, Ninomiya Squad, Azuma Squad and Tamakoma Second begins in a snowy Cityscape B. Tsuji warns Inukai against playing around in the snow and asks Aki Hiyami about the missing trion signatures, which she believes to belong to the members of Azuma Squad. He dodges Hiro Kitazoe's Random Meteor. Masataka Ninomiya orders Inukai and him to go after Tamakoma Second and ignore Azuma Squad. Tsuji delays Yūma long enough for Masato Kageura to catch up and engage him. He reaches Inukai moments after he is ambushed by Noboru Koarai and Tsuneyuki Okudera, but finds himself hard-pressed against the two Attackers. He infers that Haruaki Azuma is in position to snipe and that the snow was meant to lure opponents into a building, where their coordination would give them the advantage.

After Osamu Mikumo is sniped, Inukai proposes leaving the building as long as they know where Azuma is. Chika forces herself to shoot at the four combatants with Radar, but all survive. Inukai and Tsuji target her, with the latter intercepting Yūma as he rushes in to help her. A four-way melee breaks out as the five Attackers are gathered in one spot. Although the lack of Grasshopper limits his mobility, he manages to cut off Yūma's arm. When Kitazoe's Meteor wreaks havoc on the battlefield, Tsuji attacks Koarai, who manages to defend, only to be eliminated by Yūma, who also chops off Tsuji's hand. Before the latter can engage, however, he is sniped by Azuma, the bombardment having cleared a line of fire. The match ends with Ninomiya Squad in the lead with three points. They retain their position at the very top of the ranking.

Galopoula's Invasion
Since Azuma Squad, Kageura Squad and Yuba Squad fight in the night division of rank wars on February 19, Ninomiya Squad must have competed in the day division against Ikoma Squad, Ōji Squad and Suzunari First. They continue to rank first at the end of the match.

That night, Ninomiya Squad defends Border's Headquarters against Galopoula's Invasion. When Koskero disrupts the Snipers' fire on the army of Idras by summoning Dogs on the roof of Headquarters, Tsuji and Shun Midorikawa rush to their aid, eliminating the Trion Soldiers. After the Dogs are defeated, Tsuji is tasked with supporting Hisato Sasamori against a remote controlled Idra. After the enemies retreat, Tsuji, together with Sasamori, Futaba Kuroe and Ai Kitora, are praised by Jun Arashiyama for holding back the enemy ace. As per Shinoda's orders, Tsuji lingers in the security zone for a while.

Round Six
Ninomiya Squad fights against Kageura Squad, Azuma Squad and Suzunari First in the night division of the sixth round of rank wars. Kageura Squad and Ninomiya Squad tie at the top with three points. No Squad receives the survival bonus due to there being multiple survivors. Following the match, Kageura Squad remains in first place with a point total of 37.

Round Seven
On March 1, during the next enlistment day, Tsuji is exhorted by Koarai to fight an exceptional recruit, against whom he loses 5-2, prompting him to wonder whether he is a trained swordsman. He then spectates the match between Hyuse and Tatsuhito Ikoma, wagering that the former will win due to the latter being unable to use Senkū. Ikoma however loses due to committing a foul, prompting Tsuji to comment that the battle was really close. Since Tamakoma Second faces off against Kageura Squad, Azuma Squad and Suzunari First in the day division of rank wars of that same day, it can be inferred that Ninomiya Squad competes against Ikoma Squad and Ōji Squad in the night division.

Round Eight
The following evening, the members of Ninomiya Squad run into Chika, Osamu Mikumo, Kirie Konami and Shiori Usami at a restaurant. The latter two immediately proceed to tease a flustered Tsuji, prompting Hiyami to come to his rescue. After asking for her advice to order, he is admired by how easily Osamu can converse with girls, which Konami attributes to his mother being very good-looking. Osamu doubts that is a factor, but he claims to have never met a more intense woman, so Tsuji concludes he was forged by his upbringing. The conversation moves to Tsuji's inability to talk to women other than Hatohara and Hiyami. After declaring that the former was nice from the start, he adjoins that Hiyami was guarded at first, but that she has become much warmer since. Next they mention Hatohara's defection, with Tsuji stating that she had no choice since she could not go to the Neighborhood as part of Border. The members of Ninomiya Squad finish their meal first and leave.

On March 5, Ninomiya Squad fights the last rank war of the season against Tamakoma Second, Ikoma Squad and Yuba Squad. Hiyami warns Inukai, who is training with Tsuji, when the match is about to begin. Tsuji spawns in the western area of Cityscape B. When Ninomiya proceeds to bombard a lone trion signature to their south, Tsuji rushes to verify its identity, discovering that it is Yūma's, who has met up with Chika. Ninomiya tasks Tsuji with engaging the Tamakoma Second ace while he pressures Chika to verify whether she is able to fire. Her Hound, however, forces Tsuji to take cover. Their targets go off-Radar, but Ninomiya and Tsuji choose to continue focusing on them to ascertain whether Chika is willing to shoot to cause damage. A massive explosion gives away Chika's position. Suspecting an attack from the entirety of Tamakoma Second as well as Kazuto Tonooka, Ninomiya and Tsuji activate Bagworm. When Kōji Oki reveals his position, Ninomiya hounds him with Hornet, luring him towards Tsuji, who takes him out.

Tsuji then rushes to assist Inukai against Takuma Yuba, shielding him just in time. Yuba, however, manages to foil his sneak attack. The two members of Ninomiya Squad endure until their captain arrives. He prepares to corner Yuba with Hornet and leave them to deal the finishing blow, but Chika's incoming bombardment causes him to change targets. He tasks Inukai with intercepting her explosives and Tsuji with guarding him while he battles Yuba. Tsuji expects Yūma to go for the kill, but it is Osamu who fires at Inukai, although Tsuji manages to foil his attempt. After Yuba's defeat, the members of Ninomiya Squad gather in an open space, preparing themselves for Tamakoma Second's attack. They deflect their projectiles until Chika gives away her position, at which point Ninomiya appears to send Inukai and Tsuji after her; however, Tsuji only feints pursuing the Sniper and instead doubles back to go after Osamu. Chika opens fire against him, but not even his combination of Shield and a material barrier can protect him against her Ibis, causing him to Bail Out. The match ends in Tamakoma Second's victory, with Ninomiya Squad placing second. The three points garnered put their final score at 44, allowing them to retain their position as B-rank #1.