Arita Kouhei
Kouhei Arita

有田 幸平


August 14th


15 Years Old


Male Male

Hair Color


Eye Color







Blood type A




3rd Year, Class 2


Volleyball Club




Father, Mother, Little Sister

Personal Status

Karaoke, Cooking



First Appearance

Manga: Chapter 1

Kouhei Arita (有田 幸平, Arita Kōhei) is a highly popular and attractive male student that is also Akira Sengoku's best friend. The two got along well and seemed like the total opposites. Kouhei was a reliable leader of his own group until misfortune struck and he killed almost all members of his group. He went missing after that but returned during the Chimera-incident.


Kouhei is a tall individual who stands out a lot when compared to the others. He's a handsome man with a tough, big build who is well known for his looks and is popular amongst the females. He's not only popular, but he has vibrant green eyes and a brown spiky perm with the top of his hair being a lighter brown than the bottom. He wears the normal school uniform in a unique way. He wears the dark blue jacket over a white shirt that extends further down his body than his jacket. Both ends are slightly triangular in shape. He wears the top of his white shirt more open than normal and also wears the dark blue trousers. He also wears white sneakers. Under his left eye, he also has a beauty spot.


Kouhei was first seen as a friendly guy who had a strong-will and also cheered everyone else up. He was popular and seemed to have said a lot of nice things to everyone around him. He's extremely friendly with Akria and Rion Akagami, usually helping them out whenever he can, though still joking with them in the process about their relationship. He knows how to handle situations and was seen calming down his colleges after the guys had stolen food, where he then follows up and begins to find a new batch of food. He was optimistic and slightly condescending as he saw himself as number 1.

However, after arriving on the island, he had a slight mental breakdown killing numerous people. He had snapped from the fact that he wouldn't be able to return home and then put on a facade so that no one ever find out he murdered someone. He had showed a side of him where he doesn't want to be labelled as a murderer and would keep anyone quiet if they found out about that. He is somewhat a Sociopath.

Although after certain events with Kouhei, he seems to have returned to a person who is remorseful for what he had done and seems to have changed away from murdering people.


Arita being bullied

Kouhei being bullied

When Kouhei first went to school as a child, he was continually bullied because of his hair as it was in a perm. However, he first met Akira back then and the two became best friends from then on and from there, he began to open up and make new friends. During his time at school after that, he began to have more friends than Akira and unlike Akira, was popular with the girls. He was more than likely popular with the girls because of his looks, hence why a lot of girls had feelings of affection towards him. He was also known as the volleyball star member on the male side considering he was probably the tallest. He was usually known as number one as well most likely because he's good at sports, has good looks and was popular.


Wonderful World arc

Kouhei was first seen standing next to Akira's seat. Some girl wanted a picture of him, but he graciously asked her maybe next time. Rion knew he was quite popular as expected from volleyball team's star member. Kouhei sat next to Akira. He asked Akira if he had sex with Rion in Guam. Akira did nothing of it. He felt sad because he tried to remind Akira for his own sake. After Akira made a poem, Kouhei laughed at his seat.

As the Plane started to shake, Kouhei covered two girls with his hands. A blackout occurred on the outside and the plane started to shake even more violently. Kouhei and the rest of the passenger were knocked out during the flight into the island. When Kouhei came too, he was informed by the pilots that they landed on an island. The passengers came down through the emergency chute. They made camp near the plane. At night he heard from the pilot Masaru Tsuchiya that the radio's restored and they will return to Japan very soon. He gave Katsuragi an elbow of joy. On the second night they lit a big bonfire for the rescue party to find them. Suddenly he heard a scream nearby. A group of Andrewsarchus came to the camp. The passengers immediately closed the plane's door down. Makoto Morita, Rion and Kouhei heard a disturbance at the cockpit and they investigated it. They found a group of passengers were trying to find an answer from the pilot Masaru. He saw the radio is beyond repair. Feeling lost and the chaos surrounded him, Kouhei found a knife on the floor. He grabbed it and stabbed the pilot on the chest. Later he returned to the passenger's cabin only to find a massive panic attack on his fellow
Arita wondering where Akira is

Kouhei wondering where Akira is

passengers. He didn't do anything to help his friends. Kouhei and the passengers were forced to leave the plane because of the shaking of a group Alectroenas Nitidissima. After the exodus Kouhei formed a group of students that will follow him into the jungle. To prove his leadership he made a Bola to catch an Alectroenas Nitidissima from a tree. The boys and girls were amazed by his skill. After releasing the bird, he wished Akira to come and help him. The group talked about the plane's burning. They found Kouhei is the most reliable guy and even better than the teachers. Kouhei suggested that Akira is far better than he is. The girls didn't think so. Kouhei left the group to take a leak. At the river he recalled the event in the cockpit. Kouhei was trying to wash away the blood on his hands. He wondered where did Akira go?

Epidemic arc

His name was mentioned when Akira missed his friends and wondered how are they all doing?

Brain Loss arc

Kouhei heard some noise near his camp. He came back and found out that Kouhei's Group Boy, Ueno and Miyajima stole the food from the girls have gathered. The boys were on their knees begging for mercy. Okunoki and Makita were yelling at them. Kouhei asked the girls for forgiveness of the boys' deed. Yuki Sakuma and unknown girl agreed to that. He found trees with some tasty fruit nearby. The group cheered as their leader once again find food for his group. As Kouhei climbed up the tree and dropped the fruits into the skirts the girls are holding on. They gathered enough fruits for everyone.

At a nearby river Kouhei's Group Boy, Ueno and Miyajima found some drawing words into the ground. Kouhei came and looked at it. He immediately recognised the words and the meaning: "I saw everything." Others come and viewed the words. They don't understand the meaning. The next day they came across the same words on their path. Three days later, Kouhei sat alone in fear of the words. He knew the words were meant for him. Someone saw him killing the pilot. Kouhei started to lose his cool. In his mind he wondered who the culprit is within his group. Hikari came from behind and startled Kouhei. She gave him a photo of Akira, Rion and him on the beach. Kouhei thanked her for the photo. As his group slept through the night, Kouhei wandered into the jungle searching for the culprit. He found an open spot and he saw a person drawing into the ground. Kouhei recognised Hikari. He creeped from behind and choked her to death. Kouhei dragged her body away before someone wakes up. Suddenly he heard a noise in the jungle. Hades introduced himself to Kouhei. Kouhei ran toward him only to be stopped by a knife. He recognised it as the pilot's murder Knife. Hades coerced Hikari into drawing the words. Hades is the one who saw Kouhei kill the pilot. Kouhei had killed an innocent girl for nothing. Hades won't tell anyone about his evil deeds. Kouhei couldn't go back anymore, he will do anything to stop anyone from finding out.

The next day he told the group he found Hikari's dead body somewhere. There was a disagreement within the group whether the group should change their location. In the end, Kouhei led his group to a Limestone Cavern. Inside the cavern, Kouhei's head was struck by a falling rock. Yuki asked Kouhei if he was alright but Kouhei claimed that he was fine. When Okunoki and Kouhei were alone, Okunoki found the knife and started to blame Kouhei for getting them lost in the Limestone Cavern. They struggled with each other until Kouhei stabbed Okunoki with his knife. After that event, the effects of social-emotional agnosia were apparent. Kouhei could no longer recognize or perceive any emotions produced by others. This in conjunction with his anxiety over the deaths of his classmates and the pilot further explains why Kouhei acts irrationally during this arc.

After they found Okunoki, Kyouko, Kouhei's Group Girl and Unknown Girl with brunette hair dead next to each other, Kouhei decided to catch the murderer on his own. He left the group to hunt the killer. Yuki left the group for a while to pee. Kouhei came from behind and attacked her. Yuki struggled with him until she fell down into a flowing underground river. Kouhei assumed she will drown in the river.

At Akira's Group, Akira told the group how he met Kouhei for the first time.

Kouhei or Ueno killed Tamura and placed her near the pond where the Gerrothoraxes, Kannemeyerias and Lystrosauruses live. Kouhei asked Ueno if Nakamura would able to kill someone. He wanted Ueno to put Nakamura to the test. She failed and Ueno killed her. Ueno turned and waited for an approval from Kouhei. Kouhei told him he's done a good job. Kouhei and Ueno tied Tomo Sugiyama up, because she failed the test. Miyajima, Kouhei's Group Boy and Makita were the next ones. Kouhei ordered them to kill her. They needed to able to kill a person in order to survive on the island. Kouhei watched Kouhei's Group Boy and Makita with no eyes. Miyajima used a knife and stabbed Tomo. Kouhei complimented Miyajima and Kouhei's Group Boy for their deed. Makita was next. She didn't want to, until Kouhei came from behind and forced her hand to stab Tomo. Makita wanted to stop, but Kouhei couldn't see her eyes. Tomo died from the stabbing, Kouhei appointed Ueno, Kouhei's Group Boy and Makita as murderers too. Suddenly they heard someone's scream nearby. Kouhei suggested they leave the spot immediately. Kouhei would clean up while they leave the area. Before they left, Kouhei ordered Ueno to bring the people here to test them.

Kouhei watched as his group walked toward the spot where they kill Tomo in cold blood. In a corner he saw Yuki is still alive. He thought she drown back at the river. Next to her Kouhei saw Rion. He couldn't believe it to meet her at this place. Kouhei didn't know how to greet her. Rion and Yuki escaped from his group and flee the area. He watched as his group chased after them. Kouhei overheard Rion calling out Akira. He was astonished that Akira is alive. At the idea Akira and him together again, made him laugh. Before him lies the death body of Tomo, Kouhei knew he couldn't go back again. He used his knife to cut her body up and feed it to the Cyclotosauruses. Kouhei wondered why Akira didn't save him sooner? After he was done, he walked into the tunnel and bummed into Kanako Oomori. She recognised him from Rion's description. Akira's Group had been looking for him. Kouhei led Kanako deep into the tunnel. Kanako asked Kouhei about his head's wound, but he didn't reply back. They arrived at the ritual death spot. Kouhei revealed due to his wound he was freed to do anything he wants.

Schermafbeelding 2011-10-10 om 19.32.40

Akira finding out Kouhei is the attacker

Without warning Kouhei stabbed Kanako on her liver. He revealed himself as the murderer. Lying on the ground, she wasn't afraid of her wound. Kanako started to talk about Akira worrying about Kouhei. Kouhei was about to stab her again when Akira intervented. He couldn't see him in the dark, but he recognised Akira's voice immediately. Kouhei tried to flee, but Akira stopped him. Kanako stood up and revealed the name of the killer to Akira. Everyone was stunned by Kouhei's name, including Akira. Kouhei kicked Akira's side to free from his hold. Akira wanted an explanation from Kouhei. Kouhei stood still and said nothing. Finding a way out, he noticed two exits inside the room. Kouhei ran toward the first exit and was blocked by Kazuma Saji. After kicking and hitting Kazuma, he still blocked the exit. With no another choose, Kouhei ran toward the second exit. This time it was blocked by Shirou Mariya. Kouhei hit him down with ease. Akira's Group woke Akira up from his frozen state. Akira stood up and hit Kouhei front on. Kouhei revealed his killing spree to Akira's Group and how it started.

Out of nowhere a swarm of Cyclotosaurus had Akira's Group and Kouhei surrounded. Akira suggested Kouhei should help him carrying Kanako out of here. The others didn't believe Kouhei would help, but Akira did. Akira and Kouhei carried the wounded Kanako to safety. They escaped safety into the tunnel only to find the remaining members of Kouhei's Group. Kouhei stopped his group from attacking Akira's Group. He led his group away. Kouhei misstepped a foot and fell down a cliff. Luckly Akira came in and grabbed Kouhei's hand. Ueno and Makita didn't even try to save him. Kouhei finally realised why he helped Akira with Kanako at the first place--he always knew Akira would save him. As the cliff started crumbling, Kouhei warned Akira to let him go or they will go down together. Miina Isurugi (Fake) and Shirou then arrive on the scene. Shirou figures out that Kouhei's erratic behaviour was due to brain damage to the amygdala which led to the loss of the brain function for perceiving emotion in others. Akira helped Kouhei up despite his recent action. The group headed back where they left Kazuma and Kanako behind. They heard a rumbling sound headed their way. They started to head back where they came from. Motoko Kurusu and Yuki were above ground and they lowered a rope for them to climb up. Shirou warned the group about the flash flood was about to hit them. Akira, Kazuma, Shirou, Rion and Kouhei ran back to the tunnel. They saw a fork road ahead of them. Kouhei advised them to follow after him. Akira convinced the others to follow after him. They found themselves at a dead end. Kouhei revealed that this was the spot where he attacks Yuki and the river connected to the outside. They used their pants as Instant_Buoy. Kouhei asked if Akira and Rion have done it yet. Without warning Kouhei pushed Rion and Akira into the river. Kouhei waved them goodbye before he goes back to the tunnel.

School arc

His image was seen when Akira dreamt about school with all his friends.

Cursed Mountain arc

After walking for a whole day Akira's Group decided to rest behind huge rocks. Before Akira went to sleep, he was hoping to see Kouhei again. The next day Akira couldn't move his body. He saw a person is walking toward him. As the person came closer to him, he recognised the silhouette. It's his friend Kouhei. As he looked

Akira being strangled by Kouhei

up again, he couldn't find Kouhei anywhere. Akira stood up and wandered around to find Kouhei. Kouhei reappeared in front of Akira after Akira slipped a foot and fell down. They talked for a while until Kouhei revealed the mountain is cursed. Kouhei came from behind and choked Akira. Akira escaped his grips and when he turned back, he couldn't see Kouhei again. Kouhei emerged from the mist and started to choke Akira again. Akira escaped his grips again and Kouhei picked up a rock. Akira swung a rock at Kouhei and it passed through Kouhei's body. Kouhei knew Akira would pass through him, because he's already dead. He advanced toward Akira and Akira kept moving back. Kouhei was about to strike Akira with a rock when Akira hit his head on a big rock. Kouhei's image slowly vanished before Akira's eyes.

Animal Battle arc

His image was briefly seen when Shirou mentions the people who have died on the island already. He was briefly seen again when Akira recalled the event prior to the incident.

Pyramid arc

His name was mentioned when Rion was descending into the chute and Akira thought about him and Rion.

Failed Experiment arc

He was seen when Akira dreamt about school. During a volleyball match Akira bounced the ball
Arita fighting Chimera
to Kouhei to win the match. Kouhei thought Akira can be the main player. He later reappeared after second monster came from the trap door, but somehow was dragged back inside by Kouhei the trap door. Yuki, the one who fell to the trap door woke up and shocked that Kouhei, who she and the group thought was dead, in front of her eyes. Then Hades told Yuki to stay down. She is then shocked because she saw Kouhei fight with the second monster and told Hades to stop him. Hades told Yuki to calm down and hide. Then he told her that Kouhei can overcome the boundary limit of his strength. And then, the second monster tried to jump to the exit of the trap, but instead try to escape, it leap to Kouhei with wall as it foothold. Kouhei seems to be in trouble because the monster's speed is to fast for him. And then he stand still, waiting the monster to leap to him, when the monster almost got him, he blinds the monster's left eye with his two fingers. The monster seems to weaker and slower. Kouhei fight it and got it's right eye to and then he broke it's horn. With his win, Yuki told him to come with her to meet Akira, but he shows his hand with blood on it and says that he can't face him, and he tells her to don't tell Akira that he still alive. In the end, he and Hades move to the darkness in the trap hole and disappear.


Not much is known about Kouhei's abilities, however he was talented in many ways to the point that the rest of his group began relying on him and thinking of him as amazing. He's displayed a lot of strength and shown to be able to single handly corrupt and unfortunately murder some members in his group. He also seems to be good at sport considering he was known as the star volleyball player.

After the flood Kouhei is said to be in a constant state of adrenaline, allowing him 100% of is power. Hades describes him as the strongest man in the world.


  • (To his Kouhei's Group) "Cheer up. That airplane couldn't have flown again anyways. And even if it could have, it was mostly destroyed by those stupid huge animals already, too. I'm actually glad it burned up. Gives us a clean state. It inspired me to deal with the 'here and now'"
  • (Thinking) "N-No, I'm a murdering bastard... In which case... my only choice... That's right... I can't go backwards. Is to forge on and see things through to the end ! Yeah.. No matter what measures it takes!"
  • (thinking) "Now I see ... so that's why . I get it. That's why I helped you back there, why I stopped them from killing you. I was waiting this whole time. Waiting for you to come and save me Akira!"
  • (To Akira Sengoku) "J-Just just let go. Look the ledge is crumbling. At this rate, we'll both fall. Akira!"
  • (Thinking) "Thank you, Akira. For trusting me till the end. And also farewell my best friend, stay alive."


  • He is one of several characters to carry a real knife that isn't made of stone.
  • He is one of the few characters with weavy hair.