Satoru Tojo (東條 悟 Tōjō Satoru) is Kamen Rider Tiger (仮面ライダータイガ Kamen Raidā Taiga, Masked Rider Tiger), a character in the Kamen Rider Series Kamen Rider Ryuki. He is one of the 13 Kamen Riders that the story revolves around.
He is clearly very a disturbed man with a twisted moral background; a sort of social outcast determined to do whatever it takes to be accepted. In contrast, Satoru seemed to have shown a great amount of respect to his teacher, adopting most of Hideyuki Kagawa’s analogies on the concept of hero, although Satoru himself often ends up going against them due to his bloodthirsty nature.
Satoru presumably was a student of Seiinen University under Hideyuki Kagawa prior to getting the Tiger Deck from Shiro Kanzaki. However, through circumstances unknown, Satoru apparently revealed his role as a Rider to Kagawa, which would eventually lead to the two, along with Hajime Nakamura on the goal to close the Mirror World, making their base within Lab 401, the laboratory in which Kanzaki had been experimenting with the Mirror World. They created two fake unpowered Tiger decks to ensure Satoru's identity is hidden. When Satoru was bumped by accident to Kamen Rider Ryuki, he accidentally drops a few notes about the Mirror World which Shinji briefly read before being ushered out. While Shinji battled the Mirror Monsters he sensed, Tiger reveals himself while aiding Ryuki. This confirmed Shinji's suspicions that Kagawa's group did have some connection to the Mirror World and immediately returned to interrogate them, though he believed that Kagawa was Tiger as he explained that the Mirror Monsters were actually sent by Shiro to kill them as they had found a way to close the Mirror World. Shinji, tired of the Rider War, wished to help Kagawa, only to be told that Shinji is yet to be trusted by them. Later, Satoru secretly attempts to kill Yui as Shinji had managed to save Yui before she was run over.
After Shinji persists to help them, Kagawa offers Shinji a chance in proving he could be trusted, giving Shinji analogy of what he would do if given the choice between saving a group of people or saving a single individual, a reflection of his logic that ‘hero’ must be willing to sacrifice a single life to save the lives of millions. However, while working at Atori Cafe, Satoru's confronted by Shinji who asked him about Kagawa’s plans to close the Mirror World, only for Satoru to tell him that the job was best left to himself, Kagawa and Nakamura. However, Shinji later noticed that Satoru had been eying Yui while working, believing that Satoru had an ulterior motive to working there, believing he may been the mysterious Alternative who had been attacking Yui. While interrogating him about it, Satoru sees that Shinji can be trusted and reveals that for Mirror World, Yui Kanzaki had to die for the greater good. Eventually during the final fight with Alternative - revealed to be Nakamura - Tiger arrives to Ryuki's aid and kills Alternative, revealing himself to be Satoru. He later explains that he killed Nakamura for Nakamura's selfish agenda to kill Yui.
Later, when Shinji wanted to investigate the former Kanzaki household, Satoru decided to follow him. Along the way, the two sensed the presence of Mirror Monsters. After finishing the battle, Satoru turned on Shinji claiming that he didn’t like that Shinji was unwilling to sacrifice Yui. Before Satoru could deal a fatal blow, he was stopped by Kagawa, who did not wish for any unnecessary fatalities. Later, Kagawa would later find himself being forced into making a heavy decision. Shiro had arranged for a Mirror Monster to kill Kagawa’s wife and son. Shiro would allow the two to live if Kagawa returned Shiro the Alternative Zero Deck. Satoru loyally stated that Kagawa’s decision had already been made beforehand, firmly believing that Kagawa would readily sacrifice his family for the betterment of mankind. Satoru would be proven right as Kagawa joined a massive battle between himself, Satoru, Shinji (who had just moments ago saved Kagawa’s family), Kamen Rider Knight, Kamen Rider Zolda, Kamen Rider Ohja (who had developed a grudge against Satoru) and an entire swarm of Zelles. After the battle’s end, Kagawa checked on the condition of his family, glad to realize that they were indeed alive. Satoru was actually surprised by Kagawa’s show of compassion, to which Kagawa told Satoru that a hero was useless if he was numb to human emotions.
Satoru and Kagawa would later find themselves interrogated by Reiko, leading to Satoru identifying the woman as a threat. He made an attempt to kill her but his efforts were in vain thanks to Kitaoka. The result was a battle between the two which ended with Kitaoka being critically injured. However, Kagawa voiced his disappointment yet again over Satoru’s rash actions, reprimanding the young man once more.
The two would later find themselves having to deal with another variable in their plans. Apparently, a young Rider by the name of Mitsuru Sano wishes to ally himself with them, throwing rather exaggerated compliments at them. As proof of his worth, Sano took it upon himself to defeat a Sheerghost, which coincidentally was being handled by Shinji as well. It would turn out that Shinji and Sano appeared to be on familiar - and even friendly - terms. Satoru took it upon himself at that moment to attack Shinji. Quite unsurprisingly, Sano chose not to participate in the fight, although he did opt to cheer Shinji on. Before Satoru could kill Shinji, he was once again stopped by Kagawa. After Kagawa, Satoru and Sano returned to the lab, Sano queried on whether he would be allowed to join them. When questioned about his cheering of Shinji, Sano simply feigned ignorance, all the while saying that he’d offer his services to them for the right price.
Kagawa, despite admitting that Sano probably did not understand what exactly he and Satoru wanted, decided to allow Sano to help them much to Satoru's chagrin as they decide to abandon their base. During that time, Kagawa invited Satoru for dinner with his family, hoping to allow Satoru to realize the compassion he believed a ‘hero’ should have. Later, when Sano had located Yui, Satoru and Kagawa arrived to aid him in killing the girl, while trying to stop Shinji from interfering. However, before Yui could be killed by the Contracted Monsters of the three Riders, she somehow manages to control them into attacking their masters.
Deciding to take matters into his own hands, Kagawa attempted to kill Yui himself. However, Satoru betrayed Kagawa, claiming that in order to be a true hero, one had to win the Rider War. Because of that, Satoru would have to kill Kagawa, an act which he swiftly committed based on Kagawa's words that a hero must sacrifice those he loves. This action resulted in Satoru losing his nerve and become more crazed and being wrecked with guilt.
Satoru would be confronted by Sano later on, the latter wondering if the contract he made with Kagawa was still in effect. Satoru merely dismissed Sano, stating that his wish to become a hero did not involve Sano’s participation. Sano complied though not before noting that Satoru did not at all seem as clear as he did before. Asakura would later appear to pick a fight with Satoru, still holding a grudge against the young man for having defeated him before. With Satoru unable to pull himself together, Ouja gave Taiga a quick and painful defeat as he barely managed to escape with his life. The losing streak continued with a fight against Zolda.
Luckily for Satoru, Sano found him in his weakened state and decided to allow Satoru to stay with him until he got better. During his stay with Sano, Satoru admitted that the reason he wanted to be a ‘hero’ was because he wanted people to like him more. It was also during this period that Satoru admitted that he saw Sano as a friend. However, Satoru later contradicted himself when he interrupted a battle between Imperer and Ryuki, betraying Sano and injured the man before Ryuki interferes while he was able to kill Imperer. However, Satoru was convinced that he managed to kill Sano, rescuing Asakura from a police chase to demand a rematch, But when Asakura revealed to Satoru that he did not kill Sano and Asakura personally finished him off, Satoru panics and runs off. Satoru later ambushed Kitaoka and began a battle with him, losing as Kitaoka explained to Satoru that the moment he wanted to become a ‘hero’, was the moment he failed in his goal.
Shinji later finds Satoru in Lab 401 destroying all the notes on Mirror World, confused about what he should do now and wished that Kagawa was still alive. Later while, watching Kitaoka, Asakura and Ren participate in a three-way battle, Satoru poured kerosene all over Kitaoka’s car, as an act of desperation of destorying their only way out of Mirror World before joining the fray only to be defeated by Asakura yet again. Luckily, Satoru managed to once again escape, believing the three are good as dead after hearing the car explode. But as he runs off, Satoru saw a father and son, briefly reminding him of Kagawa and his own child. However, a truck was about to crash into the two, and Satoru sacrificed himself to save them. The injuries Satoru sustained were fatal. During his last moments, Satoru remembered what Kitaoka had told him about his wish to be a hero. As Satoru died, he wondered about how he could have been one.
Ironically, the following day, a newspaper featured an article on Satoru's good deed. He was labeled a "hero", but would never live to know about it.
After Shiro restored time to its proper course after Yui's death, Satoru was given a second chance in life with no memory of being a Rider. He accidentally bumps into Shinji with his bike, apologizing afterwards.
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