14-15 Years Old
3rd Year, Class ??
Manga: Chapter 38
Tadashi was usually seen wearing the normal male school uniform that was apart of their school. He had short black hair with a noticeable small fringe that resembled Seigou Komiyama's hair when he used to have hair. He has relatively large black eyes when compared to the other males of the series. He wears a jacket that is only slightly untied with a single button at the top of his jacket which exposes his white collarless shirt. He wears white sneakers and is relatively smaller than the rest of the people around him.
Tadashi is a light-hearted character with perverted personality and he is usually seen causing mischief with Shinji, and is similar to Akira Sengoku where they both joke around and pull a lot of pranks causing the girls to dislike them. He has been shown to know a lot about Shinji and the two are usually hanging out with each other.
Not much is known about Tadashi's past, however he is seen in a panel walking with Kouhei Arita, Akira, Rion Akagami, Aya Tokiwa and Makoto Morita when Shirou Mariya was looking at them from one of the buildings at school.
Tadashi and four other male students were working on the fence. Tadashi and Shinji couldn't decide where they put the log. Akira suggested to put it on the fence. They were surprised to see Akira working on civil duties. Tadashi found Akira's a bit crazy to choose this job. Akira didn't mind the work.
Tadashi, Shinji, Ken Tanaka and Akira heard some commotion near the center tree. They went to see what's happening. Miina Isurugi (Fake) and Takao Sugimasa were accused of vandalism of their new flag. Takashi's Group heard that Miina wants to destroy the School Camp. Tadashi and Shinji were stunned when they heard that. The group watched as Akira dragged Miina away before he can do any more damage.
Akira's Group asked around the camp if anyone has seen Miina. Later on Akira and Kazuma Saji found Miina outside of camp and brought him back to their tent.
The next day Akira was tearing the camp up. The group listened as Akira traded words with Takashi Yamaguchi. Kawai and Fujimoto intervened and tried to reason with Akira. They accidentally slipped their tongues and revealed themselves as the real culprits of Miina's abduction. Takashi's Group listened as the teachers revealed their true intention. Takashi and Shirou Mariya struck back at the teachers. With no other escape, Kawai and Fujimoto fled into the jungle.
Tadashi was in a meeting with his group. They were discussing about joining Akira's Group. Together they walked toward Akira. Takashi was impressed about Akira's speech. That's why they wanted to join his group and Akira accepted it.
Exploration Party arc
Tadashi, Shinji and Akira were spying on the girls' bath. Rion Akagami sneaked from behind and caught them on the act. Rion informed them they have to come with her.
Two days later the Exploration Party #1 returned with a wounded Akira. Shinji and Tadashi were working on the fence when they see them coming in. Tadashi stood outside Akira's tent. When Akira regained conscious everyone felt relieved. Shinji noticed everyone was worried about Akira. Tadashi cut him off before he embarrassed themselves. Shinji and Tadashi asked Kazuma who Rei Ooguro and Tooru Rinzai are. Kazuma told them about Tooru's injuries. They were speechless when they saw Tooru's cool scar.
Tadashi was one of the people who was trying to get Kanako Oomori's attention when she walked around camp.
Tadashi and Shinji were holding a log when Akira asked them about Rei's whereabout. He was holding a laugh when he tells Akira she was with Miina. They heard a scream by the shower area. Rei came out with only a towel. Tadashi and the others were shocked to her half-naked body.
Back on the camp, Shirou explained to the group what Argentavis is and does. Tadashi and the others yelled that the Argentavis might come back and hunt them. Shirou suggested to form a group each. He formed a pair with Koyomi Kanna.
Later that afternoon the Argentavis came with a flock. Luckly Tadashi caught Koyomi when she accidentally fell from her feet. Shinji, Tadashi and Asuka Takahashi were seen fleeing away at the same direction.
Shinji, Tadashi, Shuu Hikime and Ai Shioya saw Akira leading the Argentavises away from there. Tadashi was stunned to see Akira with many Argentavises chasing after him. Ai assumed he has a plan to defeat the birds. The group was stunned when Akira announced the Argentavises to come and get him. Tadashi, Shinji and [[Yuki] Sakuma] watched helplessly as the Argentavis feast on Akira. By Akira's sacrifice, Ken Tanaka was the first one to lead an counterattack. So after that, Shinji, Tadashi and Shuu followed his example. The rest of the group joined in and by before night the Argentavises left the camp.
The next morning Kako Tsuji and Tadashi found Matsushita dead on her bed along with Murata and Ken nearby. They examed their bodies but couldn't find the cause of their deaths. The group resumed their daily routine. Later on, Takao was found dead also. Tadashi and the others were listening in the conversation outside Akira's tent.
Shinji, Tadashi, Shuu and Yasunori Yamato were digging graves for their fallen friends. When Shinji and Tadashi were finished with their hole, Tadashi reported to Maya Miyauchi they are done. Suddenly Maya screamed from fear. Shirou found the cause and ordered everyone to head toward the river. After Shirou's explanation about Ancient Ticks, Tadashi warned Shinji about his hair.
Another wave of Argentavis was heading toward them. Tadashi looked scared by another flock. The group started to panic. Shinji and Tadashi were in the defence as Koyomi helped Shizuka Hatsuse up. Maya killed an Argentavis and the rest of the flock flew away.
They had to leave the camp because it is infested by Ancient Ticks. Shinji, Tadashi, Koyomi and some girl lit their Torch by Akira's order. The group watched as the camp burned to the ground. Akira's Group set their course heading toward the mountain.
At night Shinji and Tadashi were sitting nearby Kanako when they overheard about Kanako's qualities. They were wondering if her breasts are bigger then Rion's. Kanako simply replied hers are bigger.
Cursed Mountain arc
Akira's Group had been walking for two days. Takashi reminded everyone about Arctodus Simus. Tadashi recalled the bear they encounter before. Shirou explained more about Arctodus Simus.
The group started to talk how the island looks like after they reach the top of the mountain. Many people gave their point of views. Tsuji doubted they really can get off The Island. Tadashi disagreed with her. He read on the news once about some people who were saved after drifting at sea for a month. Tadashi and the others were now motivated to reach the top.
The next day Akira's Group reached the bottom of the mountain. Tadashi and the others were prepped up to climb. Some object rolled down the mountain and landed behind a bush. It turned out to be a former student. Airi Narumi, Ai, Kairi Narumi, Yasunori and Tadashi wondered what's happening up there?
The group resumed their course toward the top. Next to a rock slide the group found an Student Handbook that belongs to Noriaki Matsuki. A bit further up, they found Nagatsuka barely alive. He warned them not to climb any further.
Near the peak of the mountain Tadashi was seen walking behind of Akira and Rion. At night Tadashi, Airi, Kairi, Kazunari Murayama and Yasunori were seen exhausted from the climbing. Luckly Tooru Rinzai suggested they settle for the night. Shinji and Tadashi agreed with him. Takashi, Ryouichi, Shinji and Tadashi sleep next to each other behind a rock. Tadashi tried not to vomit.
Mami the Clairvoyant arc
His image was briefly seen during the flashback when Shirou recalls on his feeling at his friend's deaths each time.
Animal Battle arc
His image was briefly seen when Shirou mentions the people who have died on the island already.
Failed Experiment arc
Tadashi was seen again in Akira's dream, where he and Shinji explained Akira about Shirou's family and history.