Ryu Terui (照井 竜 Terui Ryū) is Kamen Rider Accel (仮面ライダーアクセル Kamen Raidā Akuseru). He receives his Accel Driver from Shroud.
He is a Superintendent appointed to the Futo Police Department's Paranormal Crime Investigation Division (超常犯罪捜査課 Chōjō Hanzai Sōsaka), and is Mikio Jinno and Shun Makura's superior. Prior to arriving in Futo, Ryu lost his family; his father, his mother and his younger sister when a Dopant froze them solid. They shattered at Ryu's touch, killing them. In his final moments, Ryu's father warned him to beware the "Man with the W Memory". Ryu, however, goes the opposite direction and is driven for revenge with the aid of the mysterious Shroud. Because it is the source of Memories, he developed a hatred of Futo and saw it as a gathering place of all kinds of scum.
Ryu Terui first made a cameo appearance at the end of Kamen Rider × Kamen Rider W & Decade: Movie War 2010 proclaiming that Kamen Rider Double is not the only Kamen Rider in Futo City any more.
Ryu received his heavy Engine Blade from Shroud early on. He spies on the Narumi Detective Agency using his Beetle Phone while he waits for his Driver to be completed. Soon after, a new crime wave starts, eerily similar to his parents' death. Thinking he has finally found his families' murderer, he steps out of hiding, revealing that he has been spying on the Agency. He then gets his Driver and transforms into Kamen Rider Accel for the first time. However, Ryu goes overboard with the case, almost killing an innocent person he believed to be the Dopant. It turns out at the end of the case that the Dopant was Ice Age, and the W Dopant was still at large, putting things in perspective for Ryu.
Though he and Shotaro Hidari clash at first, Ryu becomes an ally to the Narumi Detective Agency when it comes to investigating the Dopant crime wave, as well as picking up some of Shotaro's habits in dealing with Dopants even after losing it upon finally finding his family's killer: the Weather Dopant, Dr. Shinkuro Isaka. After obtaining the Trial Memory from Shroud and learning to use it, Ryu is able to finally take his revenge on the Weather Dopant, using the Trial Maximum Drive to destroy his Gaia Memory, after which Isaka dissolved as a result of his long term abuse of Gaia Memories.
After Isaka's death, Ryu becomes more open to the others and continues his role as a Kamen Rider to fight off the Dopant crime wave prior to learning that it was Shroud who gave Isaka the Weather Memory, though she had no idea that his family would suffer as a result. Furthermore, Ryu learns he has a unique physiology, enabling him to withstand the intense power of certain Gaia Memories and was selected by Shroud because he can resist the Terror Dopant's Terror Field. Because of this, Shroud wants him to assume Shotaro's place as Double using his hatred to enable Double to reach full power. However, Ryu has shown Shroud that he can fight with compassion and does not need to be Double to fight. Furthermore, after Philip's disappearance after Jun Kazu's defeat, Ryu had grown to love Futo with a desire to protect it, overall a complete turnabout from his initial personality.
Although he eventually rejected her advances to stay professional, he eventually started a romantic relationship with landlady/head of the Narumi Detective agency Akiko Narumi. Giving her the affectionate nickname "Chief" (署長 Shōchō) to reference her status at the Agency and to give her authority, which she found cute. During the events of W Forever, Akiko tells him the story of how people watch the Fuuto Fireworks and fall in love, and she wants someone to watch it. So, just before he and Shotaro go to fight NEVER, he promises he will watch them with her. He fulfills his promise, and they fall in love. In Movie War Core, Akiko tries to stop him from being a Kamen Rider, saying it was getting in the way of their life (and their wedding day), and causing them too much pain. However, he says he is a Rider to protect her. That, combined with what she saw through the Memory Memory about her father, convinces her to allow him to keep his Driver and Memories.
Kamen Rider Accel was part of a group of reinforcement riders led by Akira Date/Kamen Rider Birth to aid the primary riders in defeating the Rock Great Leader. All the Kamen Riders got on their bikes, with Accel assuming his Bike Form, and performed the All Rider Break attack which destroyed the Great Leader.
Ryu returned along with Shotaro and Philip also with Eiji and Goto due to Kamen Rider Wizard's summon ring which can summon any Kamen Rider. In this fight Ryu changed into Accel Bike Form that Kamen Rider Nadeshiko uses.
Several years later, Ryu halted Shinnosuke/Kamen Rider Drive and Go/Kamen Rider Mach to capture a robber who had his identity copied by Roidmude 055 because he won't allow any police officer to interrupt the crime investigation in Futo City without permission, especially the robber who was also involved in Gaia Memories as he shows the Beast Gaia Memory. He immediately notices that Shinnosuke is a Kamen Rider after he had been called by Krim. Before Shinnosuke and Go were about to save Chase, the robber started to flee and resist arrest, revealed himself to be Roidmude 077, and stole the Beast Gaia Memory. Shinnosuke and Go transformed right after Krim arrived to battle the Roidmude after it transforms into the Beast Dopant. Terui immediately joined the battle and revealed himself to be Kamen Rider Accel. After the destruction of Roidmude 077, Shinnosuke and Go bid farewell and Ryu wished them luck. It is also revealed that Terui has a daughter named Haruna when he was called by Akiko.
Ryu is a brash, and hot-headed individual, driven by vengeance for his family's deaths, going so far as to attack Double outright to prevent him from defeating the Dopant that killed his family. After marrying Akiko, and becoming closer friends with both Shotaro and Philip, he began to mellow out, seeing them as his new family, while still bringing justice to criminals and dopants alike.
- Rider Height: 194cm
- Rider Weight: 93kg
- Ability Perimeters
- Punching Power: 10 tons
- Kicking Power: 12 tons
- Maximum Jump Height: 47m
- Maximum running speed: 100m/3s
Like Kamen Rider Double, Ryu Terui transforms into Kamen Rider Accel through the use of USB flash drive-like objects called Gaia Memories. However, Accel only has access to a single form with which he fights through the use of the Accel Memory which he inserts into the Accel Driver. His Maximum Drive is the Accel Glanzer (アクセルグランツァー Akuseru Gurantsā), after charging up to a point when Accel is engulfed in orange flames he executes a jumping spinning heel kick. This can be used with Kamen Rider Double FangJoker's Fang Strizer to perform the Rider Twin Maximum (ライダーツインマキシマム Raidā Tsuin Makishimamu) finisher. While armed with the Engine Blade, Kamen Rider Accel has additional Maximum Drives.
The power of the Accel Memory allows Accel to change into a motorcycle-like form called Bike Form (バイクフォーム Baiku Fōmu). This form is accessed by removing the Accel Driver buckle from the belt when the Face Flasher (フェイスフラッシャー Feisu Furasshā) lights up. Bike form can also combine with Double's Boilder, Turbler, and Splasher units to become the AccelBoilder (Start Dash mode too), AccelTurbler, and AccelSplasher. In Kamen Rider W Forever: A to Z/The Gaia Memories of Fate, Bike Form has its own Maximum Drive after the Engine Memory is inserted in the Accel Driver and Accel switches to Bike Form called Bike Engine Dasher, which is a super-powered dash through the target.
- Rider Height: 197 cm
- Rider weight: 82 kg
- Ability Perimeters:
- Punching Power: 2.5 tons
- Kicking Power: 3 tons
- Maximum Jump Height: 90 m.
- Maximum Running Speed: 100m per 0.27 seconds
Accel Trial (アクセルトライアル Akuseru Toraiaru) is the first evolved form of Kamen Rider Accel. It is significantly faster than Accel's normal form, but it sports weaker armor and overall power. It is more than enough to make up for its weakness by being able to punch and kick at blinding speeds, as well as increasing his overall movement speed (running, dodging, etc.) to a great degree. Once the Maximum Drive is initiated, Accel Trial can only be used for another 10 seconds before being forcibly reverted back to human form, but the transformation is retained if the Trial Maximum Drive is successful before the 10 seconds are up. This form's Maximum Drive is the Machine Gun Spike (マシンガンスパイク Mashingan Supaiku), a series of multiple kicks in a row which leave a series of energy treadmarks in the form of a T, only limited by the amount of kicks Accel uses before time runs out.
- Rider Height: 195 cm
- Rider Weight: 80 kg
- Ability Perimeters:
- Punching Power: 15 tons
- Kicking Power: 25 tons
- Highest Jump: 100 m.
- Top Speed: 100 m. in 2 seconds
Accel Booster (アクセルブースター Akuseru Būsutā) is a second evolved form of Kamen Rider Accel that appears in Accel's version of the Kamen Rider W Returns DVD releases. This yellow-colored form of Accel uses the Gaia Memory Enhancing Adapter stolen from the Commander Dopant, which is attached over the top of the Accel Memory to increase its power output threefold.
Accel Booster's most notable feature is its additional armoring compared to Accel Trial, which hides a plethora of jet boosters enabling Accel to fly with great mobility, leaving large contrails of fire due to the tripled thermal energy output. Like Accel's other forms, it can utilize the Engine Blade and perform the Booster Slasher (ブースタースラシャー Būsutā Surasshā) Maximum Drive, where the Engine Blade projects a large golden energy blade to slice through the target.
- Rider Height: 195cm
- Rider Weight: 82kg
- Ability Perimeters
- Punching Power: 10 tons
- Kicking Power: 15 tons
- Maximum Jump Height: 125m
- Maximum Running Speed: 100m/4s
CycloneAccelXtreme (サイクロンアクセルエクストリーム Saikuron Akuseru Ekusutorīmu) is a form of Kamen Rider Double described by Shroud as being the ultimate form, with the change being that Ryu Terui becomes one with Philip instead of Shotaro, as their physiologies make them immune to the psychological attacks of the Old and Terror Dopants. Shroud states that Ryu's hatred and rage is needed for Double to fight at its full potential.