Ryoma Sengoku

Ryoma Sengoku (戦極 凌馬) is the creator of the Sengoku Driver and the Genesis Driver. He is 26 years old and works under Takatora Kureshima for their secret project. Ryoma Sengoku transforms into Kamen Rider Duke (仮面ライダーデューク) using the E.L.S. 01 Lemon Energy Lockseed with the Genesis Driver.

Past
During a development of the Sengoku Driver with Takatora. The first test was failed until in the present, the prototype version has been completed. Prior to Takatora getting medical attention, Ryoma got a report from Yoko that the Inves' leader called Overlord, which is the image that appears to be Deemushu existing in the ruins, without telling Takatora about the Inves' leader existence.

He was also involved in recording the fate of Yuya Sumii in Helheim and Kota Kazuraba's first transformation as Gaim in unaware fighting his own friend.

History
Sometime after Armored Rider Bravo finished off Gridon and Kurokage, Ryoma arranged a meeting about Oren's portfolio.

After Zangetsu and his troops destroy the remains of the Helheim Forest in the factory, Ryoma talks to Takatora about the new model which he replies to Ryoma that he will test the belt for humanity's sake.

After Sid sells the Lockvehicles to the Armored Riders, Ryoma was curious about Sid's plan.

Before the battle between the Armored Riders starts in the Helheim forest, he tells Zangetsu not to damage the Sengoku Driver while fighting the Riders. While the Rider battle continues in the forest, he was surprised that all 7 Sengoku Drivers are in the Helheim Forest. Just when the Inves started to enter the real world, Ryoma provided backup for Gaim to fight the Inves' outside of the Yggdrasill tower.

After testing the Genesis Driver, Ryoma tells Takatora about the features of the new belt as well as the new Energy Lockseed. He then asks him about the Inves Game, which Takatora replies to Ryoma that he will show the Beat Riders reality.

Later, Ryoma, along with Takatora, Sid and DJ Sagara (as a hologram) discuss about the disease that the citizens are having and debate on if they should evacuate the citizens. However he thinks that they should wait a bit longer to see what will happen to the Beat Riders.

While Gaim is trying to stop Ryoji's madness, Ryoma along with Takatora, Sid, and Yoko transform. He spectated as Sigurd fought and killed the Inves.

After Kota and Kaito are captured, Ryoma asked them for assistance in continuously use them as test subjects, in return giving them a greater power. While he tells them about his plan, Kota and Kaito plan to sneak off, but Yoko stops them by force. Later, Ryoma orders Yoko to let them escape without force.

Later, he tells Sid that their escape is part of his experiment and also notices some of his equipment (his Lemon Energy Lockseed and the Genesis core) are missing during the escape. Until it was informed by Sid that his equipment is currently at the hands of Kota.

Ryoma and Yoko were told by Sid about Mitsuzane's inner darkness, and thus reveals to be true as Sid suspected. After the plan to recover the Sengoku Driver from Kota have failed while Ryoma created his new Lemon Energy Lockseed and other artificial Lockseeds, he also covers Mitsuzane's action as he tells Takatora a lie about having Kota keeping the belt.

Later, as he watched the footage of Gaim in Jimber Lemon Arms fighting Marika, Ryoma decides to test the Genesis Driver. After Gaim defeats Bravo, Ryoma as Duke appears and asks Kota to transform again.

Duke then attacks Kota as he transforms, but managed to overpower Gaim. Even though he overpowers him, Duke still wants him to transform, but got distracted by Baron, which he overpowers easily. Yoko arrives where he is as Ryoma notices that she didn't use her full potential with the Genesis Driver. Later, he watches footage of Baron's fight as Ryoma is interested by Kaito's words. As Sigurd attacks Kaito, Ryoma appears to stop him and telling him that Kaito is a "guest".

He tell Kaito that the tree that was in the shrine ten years ago, was the entrance to the Helheim forest. Ryoma then takes Kaito to his lab and reveals their plan to him. He also informs Kaito that one of the seeds from the Helheim forest was planted in their world as a result of having the tree as the entrance of the forest. After giving Kaito the information, Ryoma ask him once more for his assistance, but Kaito refuses the offer and reveals his true colors. Despite his refusal, Ryoma predicted that Kaito would say that and welcomed him to the group.

Ryoma arrange a meeting of the Crack appearing on the bridge in Zawame as he ask Takatora if he will use the Scalar System. Later in the Helheim forest, Ryoma, along with New Generation Rider Marika and the Kurokage Troopers are guarding the Crack from the Inves. Kota and Mitsuzane approach to Ryoma as they were wondering what was his plan. Ryoma reply to them that he was doing the same thing what was Kota was planning as he call for truce and ask Kota for assistance. He accepts to help him as Mitsuzane returns to Zawame. Kota then ask Ryoma what will he do as reply to him that he wants to close up the Crack mention Project Ark to him. Kota was then curious about Project Ark as Ryoma explain to him that the Sengoku Drivers would save humanity. While Gaim is fighting, he was curious how would the belt save humanity as Ryoma reply to him that his Driver converts Helheim's fruits into Lockseeds and enable the wearer to absorb their energy safely. Kota wonders how many Sengoku Drivers can Ryoma make as he reply to him that he wants to make a billion at most as the population is seven billion, meaning that only 1/7 would be saved. After hearing that, Kota was mad to hear that only 1/7 in Earth would be saved as he grabs Ryoma. However, Marika stops Kota by force and reminded him his mission. After the Inves are destroyed, the Crack closes up as Kota plans to steal Yoko's Peach Energy Lockseed, which he did as he transforms and escape.

Ryoma apologized to Mitsuzane for revealing their projects to Kota as he noticed that he is willing to betray Takatora. As Gaim invades Yggdrasill Tower and changes into Kachidoki Arms, Ryoma was shocked and upset to see a Lockseed that was not created by him. He then assigned a task for Mitsuzane to investigate Kota to see who's helping him.

In the meeting, Mituszane was told by Kota that DJ Sagara is responsible for having Kota continue fighting. The group didn't believe what he said as he also inform them about the creatures that were a threat than the Inves. After the meeting, Ryoma would think that Kota would be a threat to them as they need a plan to stop him.

As Ryoma, along with Sid and Yoko investigate on Sagara, Sagara appears in Ryoma's office. Curious about his origin, Sagara reveals to them that he was the observer and mentions about the forbidden fruit. He also suspect that they were aiming something else on Project Ark. Ryoma would then explains the theory of the forbidden fruit which Sagara agrees his theory. Before disappearing, Sagara told them to find the Overlords which they may have the forbidden fruit.

While analyzing the Overlords during Baron's battle, Ryoma decides to kick Kaito off their team, but Yoko requested him to give him one more chance. Ryoma accepts her request as he decides to give his Genesis Driver, along with the Lemon Energy Lockseed to Kaito. Figuring out how to find the Overlords, Mitsuzane enters Ryoma's office as he didn't told Takatora about the Overlords. Mitsuzane then told him that they could easily find the Overlords if they follow his plan.

In his office, Ryoma looks at the Sengoku Driver, reminding him the day that Takatora was critically wounded from the Sengoku Driver test. Takatora enters his office as he asked Ryoma to create more Sengoku Driver, however he refuse. Ryoma explains to Takatora that they wouldn't have enough metal to produce the Sengoku Driver. As the alarm started to trigger, Takatora went to the Helheim forest as Ryoma suspect that the Overlords were attacking them. Surprise to see that the Overlords made their move, Sid started to worried about Takatora catching the Overlords. After Takatora learns the Overlord form Kota, Ryoma started to plan of betraying Takatora.

Ryoma betrays Takatora by hunting him down, due to humiliation and treason. However as the plan was a success, Sid reveals his true colors as he destroys the lab and enters the Crack before it completely closes.

Personality
Ryoma was one of Takatora's subordinates, and his and Sid's closest friend, a brilliant scientist in the Yggdrasill Corporation's research division who conducts experiments on the Lockseeds and is the inventor of the Sengoku Drivers and the Genesis Driver.

He is amoral in terms of using people as test subjects and expresses no interest in the Inves-based infections as his company's plan is his main focus. Despite his status as a scientist, he is dangerous to fight, proven when he easily defeated Kota in Jimber Lemon Arms and Kaito in seconds with his sheer power.

When Kota revealed his newly-gained Kachidoki Arms, Ryoma showed a bit of anger and jealousy that such a Lockseed was not his creation, displaying him as arrogant, yet as a scientist, Kachidoki Arms is an unknown factor, with the above showing distain for not knowing how Kota got the Kachidoki Lockseed and immediately picks up the fact someone is helping Kota, but doesn't know who.

Arms
Like the Armored Riders and his fellow New Generation Riders, Kamen Rider Duke's forms are called Arms (アームズ).

Equipment

 * Genesis Driver - Transformation device
 * Arms Weapons:
 * Sonic Arrow - Duke Lemon Energy Arms' personal weapon
 * Lockseeds - Gives access to Duke's form changes, depending on which arm the lock is

Portrayal
Ryoma Sengoku is portrayed by Tsunenori Aoki (青木 玄徳), who previously portrayed Aguri Kusugami in Garo: Yami o Terasu Mono. His character in the show also used a bow and arrow for weapons similar to his current character's Kamen Rider alter ego.

As Kamen Rider Duke, his suit actor is Kenji Tominaga (富永 研司) who was previously the suit actor for Kamen Rider Kuuga and Kamen Rider Bujin Gaim.

List of Appearances

 * Kamen Rider Gaim
 * 7, 9-28
 * Kamen Rider × Kamen Rider Gaim & Wizard: The Fateful Sengoku Movie Battle