Osamu Morioka

Osamu Morioka, often referred to as Mori, is a consistent contestant on Survivor: REM. He has 8th casting priority, and thus is guaranteed to appear in every season.

In Borneo, despite annoying many of his tribemates, Mori found himself in a comfortable position in the Pagong tribe as controversies around Komako Noguchi and Annaisha Hattori kept him insulated. Post-merge, after tribe leader Isamu "Shimada" was assassinated by the Tagi Alliance, Mori and friend Yutaka Furutani attempted to counter the alliance by pulling in Komako and Tagi outsider Kishou Yamaoka. However, Kishou's bizarre "alphabet strategy" was taken advantage of by the Tagi Alliance, leading to Mori's elimination.

Borneo
At the start, Mori was placed on the Pagong tribe. Although he annoyed some of her tribemates with his constant talking, he never really faced any danger during the pre-merge portion of the game. He helped vote out Takeo Hamasaki for his abrasive attitude at Pagong's first Tribal Council on Day 6.

Mori formed a strong friendship with Isao Amano, who described Mori as her only male friend. Isao was a target though because she had been sick since the game began. After Pagong lost another Immunity Challenge on Day 12, Mori voted out his friend at Tribal Council. Days later, Komako Noguchi made a comment around the campfire, saying that boys were the stupidest thing on the planet next to pigs. This annoyed all of the male tribe members, although Annaisha Hattori was blamed for the comment and was subsequently voted out.

Mori was selected as the representative of Pagong to meet with Tagi's representative, Kishou Yamaoka, at a summit off the coast of Pagong's beach. The two were tasked with selecting a name for the merged tribe, as well as designing a tribe flag. Mori came up with the name of Rattan, and Kishou added an "a" to the end, making the tribe name Rattana. Throughout the night, the two joked that the summit was set up to be romantic, although Mori denied being achillean.

After returning from the summit, Mori told Pagong that they had two minutes to gather their personal items as they were moving to the Tagi tribe for the rest of the game. After the merge, the ex-Pagong tribe members decide to vote out of conscience, not employing any strategy. Mori cast his vote against Komako saying, "Oink" (referring to his "boys dumber than pigs" comment), but the ex-Tagi members stuck together and voted out Pagong's leader Isamu "Shimada".

Mori was shocked by Shimada's elimination and quickly became suspicious of an alliance forming between the ex-Tagi members. During the Reward Challenge on Day 23, the final nine castaways were supposed to receive videos from home, which they would compete to get to watch. Mori was eager to see his daughters, whom he had been missing recently. Host Jeff Probst, however, announced that his tape did not make it in time for the challenge, leaving a very distraught Mori. Even though he did not receive a video, if he won the challenge, he would be able to send a video to his daughters. Mikihiro Yasutake won the challenge, making Mori even sadder. After Mori lost the archery challenge, he continuously shot arrows closest to the target while the rest of the tribe watched Hiro's video from home.

Mori expected to be voted out at the next Tribal Council. However, he was spared when the Tagi Alliance voted out Hiro instead. On Day 25, after Tsutomu Wada decided to stop catching fish, Mori, Yutaka Furutani, Shieri Yasude, and Midori Harada went fishing instead. The group were elated when they caught a fish, saying that they no longer needed Tsutomu to fish for them. Yutaka won the Day 26 Reward Challenge and chose to bring Mori along with him to the barbecue. Part of the reward was receiving letters from home, which made Mori extremely happy. While enjoying the barbecue, Mori and Yutaka discussed the past few votes in which the person who was voted out had always received four votes against them. The two decided to form a counter-alliance, naming it the Barbecue Alliance. They asked Komako and Kishou to join them. Komako joined them immediately, while Kishou wanted to stick to his alphabet voting strategy, saying that if he thought his vote was going to influence the decision at Tribal Council, he would vote with them. At Tribal Council, Kishou's voting strategy ended up being Mori's downfall, as the Tagi Alliance piggybacked off his vote and eliminated Mori. Mori placed eighth and became the second member of the jury. After his elimination, Mori finally got his video from home.

At the Final Tribal Council, he cast her vote for Midori to win the game, although Midori ultimately lost to Tsutomu by a jury vote of 4-3.