Shin Kamio (神尾伸, Kamio Shin) is a third-year student at Matabi Academy and the President of the Student Council. He is the owner of Yamato.
Shin is a tall and firmly built teenage boy. He has brown eyes, short black hair, and wears glasses. He is most often seen wearing his school uniform.
Shin has a very strict and serious personality, taking his duties as the student council president very seriously.
As a child, Shin was raised by his cruel and apathetic father who believed that the upper-class should cut themselves off from the lower-class and that sympathy was a sign of weakness. One day, as a test, Shin's father ordered him to call the animal control center to take away some stray dogs that Shin had been taking care of. Shin appeared to comply and notified animal control of the dogs. However, before animal control arrived, he took the dogs away to a safe place, indicating he would never follow his father's ideals.
At the start of the series, Shin makes his debut appearing before the Matabi Academy students at the first morning assembly of the new school year. After the assembly, he calls the other student council members to him. Once Tsukumoishu attacks the school, Shin appears before him along with the other student council members, declaring that the school is protected by Sandou Akitaka's barrier. He offers to overlook Tsukumoisshu's transgression if he leaves right away, but when the spirit beast refuses Shin prepares for battle. However, before he can attack, Tsukumoisshu is defeated by Yumi and Kansuke. Shin and the rest of the student council are surprised by the arrival of a seventh "pair", but realize they will have to explain the situation to Yumi and Kansuke.
The day after the battle, Shin is with the other student council members as they observe that Kaen's seal has been broken.
Two weeks after Tsukumoisshu's attack, Shin holds another meeting with the student council to discuss the apparent inactivity of the spirit beasts, despite the breaking of Kaen's seal. Later that day, a giant boar demon attacks Yumi and Kotori and Shin arrives just in time to slay the boar before it can kill Kotori.
After Yumi, Tsubame, and Tsukasa battle and defeat the spirit beast Rachi, Shin grows concerned as he speculates that more spirit beasts must have infiltrated the school, disguised as students.
Some time after the Rachi incident, Shin meets with Futaba and their companion cats to discuss the spirit beasts and their infiltration of the school. Shin decides that they will find out the mystery of the school and the center of the Futakago Barrier.
Later that night, Yumi and Kansuke are lured to the spirit beast Daraku. Shin is notified of this by two of Yumi's friends, which turns out to be a trap set by Sakira, another of the spirit beasts. Unaware of the deception, Kotori takes Yamato and goes after Yumi and Kansuke. He arrives at the tunnel leading to the forest where Daraku is, and is met by Kaiya. Fearing the academy may be left unguarded, Shin instructs Kaiya to go back and tell the others to stay put, but Kaiya decided to scope out the area first. Shin goes ahead through the tunnel, not knowing that Kaiya has been met by Hakubi, one of the spirit beasts.
After arriving in the forest, Shin and Yamato are confronted by Daraku's zombie hoard. Shin fights them off and deduces that the zombies are just puppets created by the lingering will of a fallen warrior. Shin identifies and destroys the lead zombie causing all the other zombies around the forest dissipate into dirt.
Shin is then confronted by Daraku who attempts to kill him. However, Shin manages to escape and reunites with Yumi, Kotori, and Kaiya. He states that they must locate the main body of the Daraku to defeat him. This gives Kansuke the idea to lure Daraku out of the lake using himself as bait. After Musashimaru bulls Daraku out the water using a fishing line that was attached to Kansuke, Shin delivers the killing blow. After the battle, Daraku, still alive, utters his final words, claiming that the barrier will be reversed. The group then sees smoke in distance and Shin tells Kaiya to take him with him to fly back to Matabi Academy.
Shin and Kaiya soon arrive back at the academy, meet up with Futaba, and see the Kaen-possessed Tsubame emerge from a burning building. Kaen attacks them, but Kaiya manages to shield them from the attack. Kaen then taunts them by reciting personal information about them, which he reads from Tsubame's memories, and then shows them that the Futakago Barrier has reactivated.
After Kaen leaves through the portal, Shin is determined to chase after him, despite his injuries, claiming that they cannot allow the barrier to be destroyed. Despite Futaba's protests, Shin goes ahead with Kaiya to the entrance to the Futakago Barrier. Once they reach the entrance, they see Tsukumoisshu descend from the sky.
Shin realizes that the school vice principal has been possessed by the spirit beast and tries to free him from his control. However, to Shin's surprise, Tsukumoisshu releases his hold on the vice principal, sending him plummeting downwards, and knocks Shin off of Kaiya's air board. Shin tells Kaiya to go ahead and save Kirihime and Shirayuki. To break their fall, Shin uses Yamato's ability to enlarge his sword and stick it into the ground below. The vice principal soon awakens and Shin orders him to evacuate the school.
Shin arrives back at Matabi Academy and sees the chaos unraveling as the spirit beasts attack. Shin then meets back up with Futaba and the others. He declares that, rather than going back to the entrance of the Futakago Barrier, he will stay behind and fight off the spirit beasts himself using the "Yukiguni" defensive barrier. He then orders Futaba and the others to go through the barrier and go after Kaen.
Akitaka Sandou Arc
Some time later, after Kaen has killed Kirihime and Shirayuki, Shin witnesses a giant island descending from the sky, breaking through the Futakago Barrier. Amidst the destruction, Shin orders all the students to follow the cats to an underground chamber beneath the school library.
As the island descends, a large portion of the rubble begins to swirl and come together at one point. Shin reunites with the rest of the student council and they go before a large temple that has appeared and witness the rebirth of Sandou, who hid his body among Tsukumoisshu's skull collection. The spirit beasts attempt to destroy Sandou, but he only absorbs their powers, making him stronger. Sandou then explains that six large pillars have been around since before the spark of life itself and are the source of Futakago's power, as well as all magic and spiritual power. He plans to use the pillars to return that power to the world and become the leader of the spirit beasts.
After Sandou finishes speaking, he abducts Yumi, and knocks Shin and the other student council members away. They soon awaken in a forest with Kibao and find that they cannot use their powers. Nevertheless, Shin declares that they must do something to stop Sandou.
Shin and the others then discover an arrow that was shot by Tsubame that leads them to the magic formation that Sandou is using to conjure his powers. They destroy it, which enable Kansuke to deliver a killing blow to Sandou.
With Sandou defeated, Shin and the rest of the student council meet up with Yumi and Tsubame. Kaen then appears before them, stating that the spirit beasts have scattered and he will try to keep his existence a secret. The group then realizes they can no longer communicate with their cats. They are disappointed, but know it is for the best.
Three months later, Shin and the other students of Matabi Academy have relocated to an unused school and readjust to normal life.
Shin tends to fight alone using his sword to perform powerful attacks. His cat Yamato is able to merge with his sword, changing its appearance and strengthening its attacks