Kyosuke serves as one of Ruri Kirishima's security guards and leader of his squad. He first stands watch at the hotel entrance with a group of his men and prevents Chiaki from entering, oblivious of the fact that she is a hired magical girl guard.
His group tries to prevent a group of Yakuza from getting into the hotel, but is affected by magic and completely blanked out until the intruders leave the building again. Soon after, Ruri's assistant Noriko calls him up on orders of Warmaster Matsuda. He first checks the security camera footage, only to realize it has been compromised. He desperately tries to recover any material, but finds nothing.
Up in Ruri's suite, he is interrogated by the Warmaster, intimidated by stories of her shooting kneecaps out, as well as Sayaka's presence. He reports how the Yakuza got in, explaining that their leader held up a card similar to those of children's card games, which seemed to burn with a green light and made his whole squad blank out.
He also explains about the security camera and apologizes on behalf of his men, offering himself up to take the punishment for them. Chiaki admits that they could not have done anything about magic and instructs him to divide his men in small teams to patrol the area, place new cameras and to give her a headset on their communication frequency.
Before he leaves, Chiaki asks for his name. He introduces himself and leaves to put her orders into action. Outside the room, he quickly dashes off, bumping into Noriko an the way. Before leaving the hotel, Sayaka drags him behind a wall where they have a hushed conversation.
Later during the day, Kyosuke serves as Ruri's driver, taking the idol and her companions to their appointments in an armored Hummer. In Mitakihara stadium, his men secure the perimeter while Kyosuke remains in the main area, catching glances of Chiaki every now and then, contemplating how to talk to her.
After a while the magical girl waves at him and he nervously sits down a few seats away in uncomfortable silence. When Chiaki finally breaks the silence, he apologizes for staring and hands her a headset, explaining that they had a new one delivered from their headquarters since a lady should not have to use one of their used ones.
Chiaki inquires about his stares again, and Kyosuke explains that he never worked on a high profile security mission before and never met a magical girl, thinking his comrades were fooling around with the new guy when they insisted they exist.
Chiaki asks how Kyosuke got into this business, curious due to his refined speech. He explains that he used to undergo formal training as a violinist, but many things happened and it did not work out in the end. While he was looking for a different line of work, a friend got him into his agency and after two tries, he managed to qualify and barely made it through basic training. Afterwards, work was relatively easy.
Noticing how Kyosuke frequently looks at Sayaka, she wonders if there is something between them. He refuses to delve into the matter, but is glad to hear that Sayaka has good friends after Chiaki jokes about the two of them not trying to kill each other for a while. He assures that his ties with Sayaka will not complicate the mission in any way before moving out to join his men on their patrols.
When he notices Chiaki climbing up to the maintenance areas while talking on the phone, Kyosuke sneaks up on her. He unsheathes his combat knife and tries to attack, but is easily repelled, thrown down and pinned to the ground with a gun on his forehead.
Struggling to keep his composure, he apologizes and wants to explain himself. Under the pressure of her gun, he tells Chiaki that there is a tradition of the team leader trying to get a souvenir from any magical girl they work with, like a scrap of clothes from her uniform. He tried to take a part of her back ribbons as the tradition also calls for a knife to be used without the magical girl noticing.
He admits that the tradition is stupid, but also feels that this game is needed to make it so that the men don't feel obsolete among the superior strength of magical girls. As one of the few remaining regular security agencies, Kyosuke wanted to give his men this morale boost.
After Chiaki gets off and pulls him up with his tie, Kyosuke explains that only a few ever managed to accomplish the feat and that those who do get a huge payment raise and better equipment. On the magical girl's request, he contacts HQ to inquire about the last one to succeed. A now retired man going by Ol' Jack or Big Boss managed to get a bead from the Sixth Warmaster's necklace while they were hunting each other in a jungle by ambushing her in her after meal sleep.
Kyosuke apologizes again for ambushing her, admitting that he is way out of his league. Chiaki tells him that she has an idea for him to still get the Sparkles Award, but will tell him about it later. He accompanies her back to the stage where Sayaka threateningly shouts at him to get the cars ready, sending the young guard off in a hurry.
A bit later Kyoko and another girl arrive at the stadium and Kyosuke contacts Chiaki to ask if he should let them in right away. She confirms, reminding him about their earlier conversation, to which he replies with the hope of not getting set on fire by Kyoko again. He lets the pair of magical girls in and chats with Kyoko for a while until she hits his arm with a hard punch, laughing all the while.
Kyoko hands a bag to Chiaki and a heavy suitcase to Kyosuke, who wonders if it contains a high caliber rifle. Before leaving, she tells him not to slack off and punches his guts. Iori starts to scold Kyoko, but Kyosuke tells her that he is okay, surprisingly still standing, and that the punches are just an in-joke between them. The Eversor compliments his endurance, pats his shoulder hard and leaves with her partner.
Recovering from the blow, Kyosuke reassures the concerned idol that there is nothing behind Kyoko's punches and shows a drawstring to Chiaki, a piece of the Eversor's clothes. She compliments him on snatching it away without being noticed and assures that she will back him in case his agency does not believe he stole it from a magical girl. She takes the suitcase to get it to Sayaka herself and Kyosuke, suddenly feeling sick from the punch to his guts, excuses himself and runs off.
Back at the hotel, Kyosuke and his men check the building for any intruders before Ruri returns to her suite. Some time later, he informs Chiaki that a group of six girls has arrived, a Vindicare squad and the Callidus Rank Leader Enishi Karasawa. He asks how to proceed and is told to direct them to the penthouse, but to switch the location of Ruri's room with that of Sayaka.
The next morning, Kyosuke gives his men a bright briefing, everyone being in high spirits due to their leader claiming the Sparkles Award. After lunch time, Chiaki calls for a final security meeting and gathers everyone in Ruri's suite. Kyosuke and his men will drive them to the concert and back on cleared routes, guard the entry and exit points of the stadium and keep watch over Ruri at all times.
Kyosuke asks about Chiaki's plan for emergency extractions, and Enishi mentions that they usually have a Callidus assume the appearance of the principal to lure hostiles away, offering herself for the role when needed. Chiaki adds that she should also disguise her and Sayaka since they are easily recognizable and would give the real Ruri away. Enishi compliments the plan and Kyosuke assures that his men would be able to pin hostiles down long enough for the extraction to complete.
Chiaki adds that if anyone notices a golden weapon, they are to inform her immediately and refrain from engaging or picking it up. Kyosuke compares it with the make of Chiaki's desert eagle and asks for details, but Sayaka tells him that he doesn't need to know about magical girl things. The meeting concludes and Kyosuke leaves to give his men an update.