Five years ago, Hiiro was a student at a prestigious doctor university. He had a girlfriend named Saki who deeply cared for him, going so far as to leave him so that he could prioritize his studies. When Zero Day occured, Saki became infected by the Bugster virus and created Graphite, a Bugster so powerful that not even Taiga Hanaya (as Proto Snipe) was able to defeat him. After Saki asked Hiiro to become the best doctor in the world, she vanished from the world. Since then, Hiiro holds a grudge against Taiga Hanaya and Graphite as well. BANG, That Jerk is Coming! A Hollow Beating in the Heart!
Saving Satsuki and Mizuki
Several years prior to becoming Kamen Rider Brave, Hiiro saved the lives of Mizuki Mizoguchi and Satsuki Ogimachi, both of whom would assist him as nurses, vowing to be the best aid for the best doctor in the world.
Return to Japan
Hiiro was working for a prestigious hospital in the United States before being called back by his father to handle the Bugster outbreak. Given the Gamer Driver and the Taddle Quest Gashat, he had just arrived in Japan when a second candidate, pediatrics intern Emu Hojo, had been chosen to join the CR as Kamen Rider Ex-Aid. I'm a Kamen Rider!
Debut as Brave
Hiiro appeared in CR after Emu receives his special Stethoscope. He wasted no time in alienating and belittling Emu, responding to the latter's presence with "No thank you". He arrived with two of his nurses to the location of Rensuke Natori, the next Bugster patient. Transforming into Brave Quest Gamer Level 1, he extracted the Aranbura Bugster from Rensuke. However, before he could continue as Quest Gamer Level 2, Brave and Ex-Aid were attacked by a black Ex-Aid, allowing the Bugster to escape.
Frustrated about being interrupted, he asked Asuna to alert him when the Bugster reappeared. He proceeded to eat cake, seeing that as more important than helping the patient, infuriating Emu. Hiiro found Emu later when Aranbura had taken Rensuke's fiancé Asami hostage. Ignoring Emu's warnings (and calling him a failure of a doctor for letting the well-being of his patient get in the way of fighting the Bugster), Hiiro transformed into Brave Quest Gamer Level 2, and attacked Aranbura using a sword generated in the game map, which later turned into the Gashacon Sword. Brave and Ex-Aid fought the Bugster together, although Brave was the one to deliver the final blow on Aranbura using Taddle Critical Finish (Ex-Aid attempted to finish the Bugster using Mighty Critical Finish).
Nevertheless, the incident would push Emu to stay in the CR, not trusting Hiiro with patients due to his apathetic nature. Another Prodigy with No Thank You?
The Return of a Nemesis
Hiiro was disgusted to learn that Taiga Hanaya had gotten a Gamer Driver and Bang Bang Shooting Gashat, becoming Kamen Rider Snipe. Finding Snipe and Ex-Aid fighting the Revol Bugster, he transformed into Brave and attacked Snipe in order to take the latter's Gashat & Gamer Driver. The two fought briefly before Ex-Aid reminded them of the bigger priority. However, Revol was able to lower Ex-Aid and Brave's health meters to critical levels. Brave decide to cancel his transformation, deeming it too risky to fight. However, Ex-Aid bravely fought Revol & defeat him (Which actually turned to be a clone) using Mighty Critical Finish. Snipe finished off the real Revol using Bang Bang Critical Finish. After Taiga confiscated Emu's Gashat, Hiiro said that Emu reaped what he had sowed and that that was the consequences if he operates with high risk. Much to his confusion, Emu seemed unbothered, as Yuki had been saved. BANG, That Jerk is Coming!
Lazer Makes His Appearance
Hiiro and Poppy confronted Kuroto when the latter went to CR to apologize for underestimating Taiga. Hiiro requested one of each kind of Gashat. His request was denied, as only one of each Gashat existed, but he was assured that more Gashats would be ready in a few days. The conversation was interrupted by Emu, who requested Hiiro's help in helping Yoshitaka Nishiwaki, the newest Bugster victim. Hiiro learned of the fourth Rider, coroner Kiriya Kujo, Kamen Rider Lazer. Hiiro observed Lazer and Snipe take on the Bugster after it emerged from Nishiwaki, but joined the fight after the Motors Bugster was separated, primarily to keep Snipe from finishing it off. His duel with Snipe was interrupted by the black Ex-Aid. Both riders were brought to their knees by the black Ex-Aid, only for the intruder to disappear without a trace. Weakened by the ambush, Hiiro could only watch in frustration as Taiga walked away. An Operation Called Dash!
Frustrated over having been defeated by Genm twice, Hiiro would confront Dan alone as he visited CR, demanding that he give him a VR simulation. Dan explained to Hiiro that Genm used the Proto Mighty Action X Gashat, stolen on Zero Day, which essentially had the same parameters as Ex-Aid. Knowing this, Hiiro became more flustered and demanded that Dan simulate him right now to which he complied Dan. Simulating the Quest Gamer, Hiiro faced Genm as opposed to a Bugster Virus. Instructed by Dan, Hiiro transformed into Kamen Rider Brave Quest Gamer from Level 1 to Level 2 before activating his Taddle Critical Strike finisher using the Kimewaza Slot Holder. Though clearing the simulation, Hiiro was not satisfied since he knew that the real Genm was not that weak. To evade further questions, Dan decides to leave for checking the new Gashats. When Hiiro checks the screen, it shows that Dan had set the difficulty level to Easy, which confuses Hiiro. Brave Chapter
Encountering Graphite for the First Time
Sometime later, Kuroto contacted Hiiro and Poppy to inform them that the four new Gashats were stolen, sending them security footage of what seemed to be a man breaking into Genm Corp. Within seconds of this announcement, Emu called Poppy about another gaming disease patient. Upon arrival, Hiiro and Asuna recognized the "victim" as the man from the security fotoage. Hiiro demanded the Gashats from the patient in exchange for his help, leading to an argument with Emu and eventually the thief escaping the premises.
While Hiiro and Emu lost the thief, they were quickly confronted by a Collabos Bugster. Much to their shock, not only was the Bugster separate from its host, but it had been installed with the Gekitotsu Robots Gashat. Emu and Hiiro transformed to Ex-Aid and Brave, only to be overwhelmed by the Bugster's sheer strength. To make matters worse, the fight was interrupted by the black Ex-Aid, who brought the other Riders to their knees before escaping with the Bugster. The only form of clarity was from the sudden appearance of Kiriya, who claimed that he had seen the black Ex-Aid's true identity: the Gashat thief. Kuroto arrived in CR sometime later to discuss the game plan. Hiiro lost his temper with Emu after the latter pleaded to try and help the thief. Reminding Emu that they were dealing with a criminal, he reprimanded Emu for getting involved with his patients, citing Taiga taking the Migthy Action X Gashat as an example. He claims that he's sick with Emu idealism, which the latter claims that Hiiro isn't a real doctor before fleeing away.
Hiiro later appeared at Robots Collabos location along with Emu and Asuna. Taiga, Kiriya and Genm Sports Action Gamer Level 3 also appeared not too long after. Hiiro, Taiga and Kiriya trasnformed into Brave Quest Gamer Level 2, Snipe Shooting Gamer Level 2 and Lazer Bike Gamer Level 1 to fight Genm and Collabos. However, Genm and Collabos manage to defeat them easily with the help of the thief, which latter shown to be Graphite all along. Hiiro cancel his transformation, stating that this battle is too risky to handle. Hiiro later witness Emu, defeating Robots Collabos and Genm using Mighty Critical Finish and Gekitotsu Critical Strike respectively. Everyone Gathers for a Clashing Crash!
Become Beat Quest Gamer Level 3, Second confrontation with Graphite
Hiiro appears in front of Kiyosora College of Music, muttering Graphite's name and thinking about Taiga's reaction against Graphite before noticing Emu and Asuna, who were attempting to find a patient. He later appeared when the patient showing symptoms of Game disease. Hiiro suggests to let the disease take over first so that they can operate her easily. After the patient turned into Bugster Union, Hiiro transformed into Brave Quest Gamer Level 1 and quickly extract the girl from the bugster, which is later shown to be Beat Collabos. However, Graphite suddenly appeared and claims that he's infect the girl with two game viruses (Gekitotsu Robots and DoReMiFa Beat). This prompts Emu to join the battle as Ex-Aid Action Gamer Level 1. He and Ex-Aid then confront Beat Collabos. The Bugster then attack Ex-Aid and Brave in similar manner as Rhythm game. Although Ex-Aid manage to get a Perfect, Brave get a Miss and damaged. Graphite soon transformed too and join the fray, although soon interrupted as Taiga appeared, already transformed into Snipe Shooting Gamer Level 2. Ex-Aid then directly transformed into Robot Action Gamer Level 3 and Brave transformed into Quest Gamer Level 2. Graphite attack the trio using Gekidoryuga, heavily damaged Brave and Snipe despite their attempt to counter it. Their lives somehow saved by Genm Sports Action Gamer Level 3, ordering Graphite to retreat.
After the Battle, Hiiro confronts Taiga. He ask if Graphite was the one Taiga failed to kill 5 years ago. Taiga states that it's not Hiiro's own business anyway. This frustrates Hiiro as he chases Taiga and demands the answer. Taiga mockingly said that he's been forgetting things lately. Hiiro then tries to punch Taiga, but Taiga easily blocks it using his right hand. Hiiro states that he could have saved a girl called Saki back then. Their fight was stopped by Emu, and Taiga challenged Hiiro to defeat Graphite if he can and reveals that Graphite is indeed the one who kill Saki before leaving. Hiiro then clenched his fist in rage.
Hiiro later appears at Beat Collabos location. This time, however, he aims for Graphite [who was at scene as well]. While Emu transformed into Ex-Aid Robot Action Gamer Level 3 fight the Beat Collabos and Bugster minions, Hiiro transformed into Brave Quest Gamer Level 2 and attacked Graphite, but was easily defeated. Graphite provoked Brave by claiming that Saki had already given up on him, causing him to snap. Brave cast his Gashacon Sword away and attacked Graphite again, but was once again easily defeated. Just before Graphite could finish Brave by using Gekidoryuga, Ex-Aid saved him by taking the hit directly, cancelling Emu's transformation. Emu pleaded to Brave that Saki kept her Buster virus a secret since she didn't want to bother his studying. Reminiscing Saki's last words, Brave realizes that Emu was telling the truth. This ignites Brave's spirit as he becomes determined to finish Graphite off.
Brave uses Stage Select to enter a forest-like environment, and using Taddle Critical Finish (Ice ver.), Brave manages to defeat Beat Collabos, acquiring the DoReMiFa Beat Gashat. Using the newly acquired Gashat, he transforms into Beat Quest Gamer Level 3 and uses rhythm-based attacks to fend Graphite off. Using DoReMiFa Critical Finish, Brave quickly manages to defeat Graphite; however, Graphite manages to flee, cursing Hiiro in the process. A Hollow Beating in the Heart!
Second confrontation with Genm
Hiiro was seen along with Haima at CR. After scolding his dad because he talked too much, Hiiro decide to operate the patient. He quickly notices Emu and order him to stand aside, which the latter refuse as he can't let Hiiro to do things his way. Nevertheless, they transformed into Ex-Aid Action Gamer Level 1 and Brave Quest Gamer Level 1 respectively, and also successfully extract the bugsters (Chambara & Combat Collabos) from the patient. However, sudden intervention from Genm Sports Action Gamer Level 3 allow the bugsters to successfully flee, even after Ex-Aid and Brave transformed into their Level 3 forms.
Back at CR, Kiriya appeared in CR after Haima carelessly drop his folder in front of the CR Door. However, all of them (Except Haima since the latter is still obvious about Kiriya) starts to not believe him. Hiiro asks why Kiriya lied to them by saying that Genm is Graphite. The latter said that it's to protect them from Harsh Truth. Unfortunately for Kiriya, they all goes to their own business. Hiiro then asks his dad to do some research regarding of Kiriya past.
Hiiro later appeared again at Chambara Collabos location, warned Emu to not trust Kiriya before transforming into Brave Quest Gamer Level 2. However, Genm Action Gamer Level 2 appeared and fight with Brave. He later saw that Genm is Parad. He warned Emu that Kiriya is a complete liar, there is no truth in his words before he left. The Reason for Some Lies!
The Rematch with Taiga
At night, Haima said to Hiiro that Taiga had abducted the Bugster that infects Yoshio. Hiiro coldly scorns that Taiga had lost all his morals, ever since Taiga failed to save Saki back on Zero Day, and that her death means nothing to him. Hiiro decided to accept Taiga's challenge and swore to claim Taiga's Gashat and Gamer Driver, ignoring his father's warnings.Men, Fly High!
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