Mitsuzane Kureshima

"Kota, use this!"

- Ryugen's quotes when throwing a new Lockseed to Gaim

Mitsuzane Kureshima (呉島 光実), nicknamed Mitchi (ミッチ) is Kamen Rider Ryugen (仮面ライダー龍玄 [リュウゲン]). He uses the Budou Lockseed.

Becoming Ryugen
As Kota returns from the Helheim Forest, Mai and Mitsuzane visit him. As they are wondering what happened to Kota, he tells them that he encountered a white Armored Rider (Zangetsu), who attacked him with no hesitation and thinking that he kills Yuya in the forest. He then tells them the true purpose of the Inves Game. After telling them, Kota started to feel scared after the incident as he quits the team. Mitsuzane decides to buy the Sengoku Driver from Sid, who knows his brother and the company that his father is working for. Sometime later, after Team Gaim is done dancing, Team Invitto's leader, Hideyasu Jonouchi appears as he duels them. Mitsuzane then transforms into Armored Rider Ryugen as he fights an Inves.

Inspiring Kota
After he transformed into Ryugen, he defeated Hideyasu's Inves as he gain a new Lockseed from him. Sometime later, he had a dream in which the mysterious girl tells him about the fate using the Sengoku Driver. On the next day, Mitsuzane discusses with Team Gaim about Baron's alliance with other teams until Kota appears. Kota then tells him that the Sengoku Driver is like a curse and the true purpose of using the belt, but Mitsuzane thinks that he can fight his own battles with the Sengoku Driver. Later, Kaito arrives to challenge Mitsuzane to test his strength. He transforms into Ryugen as Baron summons 2 Inves, which one of them is of a higher class. As Kota and Mai arrive, Ryugen was getting hurt as Kota tells him to retreat. However, he refused to give up when Kota and Mai is watching him fight. Kota was curious until Mai tells him that he made Mitsuzane strong which inspired him. Kota decides to fight with his own power as he transforms into Gaim and helps Ryugen. While fighting, he tells Baron that people don't use strength to show off power, instead it can inspire others to get back up. Ryugen then throws the Ichigo Lockseed to Gaim, which change him into Ichigo Arms. With the new form, Gaim and Ryugen finishes off the two Inves. Ryoji and Hideyasu then appear and transform into Armored Riders Kurokage and Gridon respectively, which shock Gaim, Ryugen and the members of Team Gaim.

Bravo and Suika
After they transform into Gridon and Kurokage, they betrayed Baron and finishes him off. Gaim and Ryugen attack the new Armored Riders and finishes them which they gain their Lockseeds. Sometimes later, in the garage, Mitsuzane tells his teammates that they could be in first place as they celebrate. Later, he returns to his home and he discovers that his brother had a Sengoku Driver in his briefcase. As he is about to walk away, Takatora stops him and wants to talk to his brother. Before they could start, Takatora got a call from his work and as he leaves the room, Mitsuzane steals the Suika Lockseed before his brother reentered the room.

When Mitsuzane and the rest of Team Gaim dancing, Oren interrupts, challenging the Armored Riders of the team to fight. Bravo quickly uses all of his winning prize Lockseeds to unleash Inves to the fight while purposely letting them running rampant. Mitsuzane/Ryugen give Kota/Gaim his stolen Suika Lockseed as he transform into Suika Arms and destroy the Inveses. But one still left and eat all of the Lockseed to become an Evolved Inves while running rampant again. Gaim Suika Arms and Ryugen (riding Sakura Hurricane) chase the rampant as they finally destroy it. Mitsuzane reveals to everyone that they are now on the top among Beat Riders as they celebrate with a cake from Charmant, much to Kota's dismay.

Inves Outbreak Part 1
While examining the Suika Lockseed, Mitsuzane exams the Lockseed that is now unresponsive as the lock loses it colors somehow after use. When Mai went missing, both Mitsuzane and Kota got a call at the same time until Kota witnesses the plants from the Helheim Forest, which was told of before to Mitsuzane and Kota goes to rescue Mai. Mitsuzane then got a call from his teammate that Sid appeared in their garage. He ushers the others out of the garage when Sid reveals he is looking for information on the Suika Lockseed. Mitsuzane admits that he stole it from his brother, but he reminds Sid that he is also a Kureshima, and makes a request of the Lock Dealer: obtaining the same Lockvehicle as Baron's (Rose Attacker) in order to enter Helheim to rescue Mai and Kota. With Gaim is at a disadvantage, Ryugen arrives in time as both finished the remaining Inveses. Once the Inves are defeated, Gaim reveals to Ryugen that the Helheim Forest is where the Lockseeds come from, prompting Ryugen to pick one off of a tree, transforming it into the Kiwi Lockseed. He and Gaim arrive in time to find Mai being protected by Baron from a Dragon Inves and assists him, as well as finding an escape portal before it closes. With the Riders managing to escape the forest with Inves following them, Ryugen covers Mai away from Gaim and Baron's battle. Ryugen and Mai witness that Baron has a Mango Lockseed to transform into Mango Arms as Gaim transformed into Pine Arms and finished off the Inves with the combination of Pine and Mango finishers. When Mai speaks about being stuck in Helheim, Mitsuzane informs them that some of Inves could break out into their world, and soon the Inves Outbreak will begin as the Riders must be involved to hunt them down for good.

At Team Gaim's garage, Mitsuzane and his teammates had a meeting about the Inves outbreaks and arranged an alliance with the other Armored Rider competitive Beat Riders. However, it failed as it wasn't their problems. Before Mitsuzane entered his home at night, he looked at the Suika Lockseed he held and noticed the color on the lock is normal, then hid it. When Takatora arrived, he told Mitsuzane to make sure the gate was locked since a Beat Rider broke in and stole something. Takatora then asked Mitsuzane about his opinion on the Beat Riders. In the morning, Mitsuzane arranged a meeting to search for the plants from Helheim that appeared in their world, but failed again, until Kota realized that the Inves only search for a fruit that is similar what happened when Banjo's fruits when he was attacked by the Inves, which gives Mitsuzane an idea to bait the Inves out. He and Kota head back to Helheim to find a premature lockseed, before Mitsuzane brought a plastic bag. Knowing the Inves would eat a matured Lockseed may transform into a massive form, according to Mitsuzane, the Lockseed transformation can only be picked by those who wears a Sengoku Driver, so Mitsuzane gave his belt and Budou Lockseed to Gaim to pick the premature Lockseed and put it in the plastic bag.

While baiting the Inves out, their plan is shortly interrupted when Gaim humiliated himself when the Inves arrived in a few minutes and had a chance to attack it. Before the Inves escaped, Ryugen attached a tracking device where the Inves currently is. Once Kota and Mitsuzane arrived at a factory where the Inves is, they witness the place is full of plants appeared around the factory and one worker was killed by it. When the Inves arrived, Mitsuzane and Kota fought back as they be able to finish off the Inves. Once the high leveled Inves is finished, Kota and Mitsuzane hide and finds out there are more Elementary Inves that have come through until the white Armored Rider called Zangetsu arrived. While watching Zangetsu fight and had his troops burned the plants from Helheim, Mitsuzane realized that Zangetsu is his brother (although he is not sure about it), as seen with the belt's faceplate. Kota snaps Mitsuzane out before the flames almost burned them, they managed to escape the factory without being spotted.

All Armored Riders Gathering, Battle Inside Helheim Forest
Sometime later, Mitsuzane tells Kota that he would face the white Armored Rider alone, but Kota was against it. This gave him a plan of creating a new game that have Armored Riders gathering Lockseeds in the Helheim forest. As they manage to ask other teams to join the new game, they meet up Sid to buy the Lockvehicles. Before the game could start, Mitsuzane tells him that the Armored Riders will distract the white Rider including himself as Kota will see what was the scientist are doing in the forest and hoping that they would know what happened to Yuya. On the next day, the Armored Riders have gathered with Kota hiding, however Oren also arrive with a Lockvehicle. Before they could start, Inves appear to attack them. As they transform, the Armored Riders decides to go to the forest one by one, until Ryugen is alone. After all the other Riders went to the Helheim forest, Kota appears and transforms which lets Ryugen enter the forest, while Gaim distracted the Inves.

Upon entering the Helheim forest, Ryugen enters in Kiwi Arms states for an unknown reason, he is then attacked by the Inveses but managed to destroy them. He is soon encountered by Zangetsu, upon getting attacked, he is saved by the sudden appearance of Kurokage. Upon Kurokage's Sengoku Driver being accidentally destroyed, Zangetsu got a call that the Inves are attacking his researchers, which is also that Mitsuzane soon hears his family's surname, which finally confirms his brother as the white Rider. As he arrive in the ruined based camp where the researchers were, he found multiple Lockseeds and took them all as evidence for Sid. As a promise, he and Kota gives Sid a box of Lockseeds and tells him that they won't be their test subjects. Team Gaim soon celebrates Christmas Day as a victory.

Inves Outbreak Part 2 and Multiple Kurokage
In their garage, Kota and Mitsuzane have gathered information that they learned from the forest and the connection between the Yggdrasill Corporation. After that, he tells Kota that they should never transform when Inves start to attack, so the company wouldn't get their data. Their fans approach them and ask Kota and Mitsuzane for an autograph and to see them transform, but they ignore them, until Inves attacks them. Kota transforms and finish the Inves as Mitsuzane warned him not to transform. As they see the Yggdrasill researchers, they hide and see the researchers as Kurokage and burning the plants from having people knowing the forest. Later, in Drupers, Kota thinks that they should reveal them the truth of the Inves Game, but Mitsuzane refuses and decides to keep this as a secret between them. Kota then asks why shouldn't reveal this to their team, Mitsuzane responds that he doesn't want them being in danger. Upset of learning the truth of the Inves Game, Mitsuzane thinks that their best solution is to destroy or throw away the Sengoku Driver, so their team wouldn't need to worry about them and Yggdrasill wouldn't be controlling them. As a group of Inves start to attack people, Kota transforms, but Mitsuzane tries to stop him by force. While Gaim is fighting, he was about to transform, but hesitates because of his fear of the company getting his data.

Possible Future
In a possible future, Ryugen stood by Zangetsu's side and his army of Inves and Suika Arms Armored Riders, watching the battle between Gaim and Baron's armies, assuming that his brother will know his identity.

Personality
He is a member of Team Gaim and Kota sees him as his younger brother. He is the son of a director of the Yggdrasill Corporation and attends an elite high school, a side of him which he keeps hidden from everyone. Living under his brother's shadow, he wants to live freely and break free from the path established for him, as such he sees Team Gaim as family due him being able to be himself while there.

He also respects Kota as a role model, basing his own beliefs around Kota's and always want to do more to help others. He also harbors a secret crush on Mai, which drives him to ask for a Sengoku Driver from Sid and become a rider himself, when Mai is at wit's end due to Kota being shaken to the core after the encounter with Zangetsu.

Despite having a cheerful and optimistic personality, in reality, Mitsuzane also has a dark personality. He will use his own status or a current situation for his own benefit and sake. As shown, he convinced Sid to give him the Sengoku Driver, which Mitsuzane tells Sid that one day he will surpass his brother. Mitsuzane also forced Sid to give him a Lockvehicle or else Mitsuzane would tell Takatora that Sid is the one who gave Kota the Suika Lockseed. Mitsuzane also stole the Suika Lockseed from his brother without any guilt. Currently, only Sid knows about Mitsuzane's inner darker personality.

Arms
Like with the other Armored Riders, Kamen Rider Ryugen's forms are called Arms (アームズ).

Devices

 * Sengoku Driver - Transformation device
 * Arms Weapons:
 * Budou Ryuhou - Ryugen Budou Arms' personal weapon
 * Kiwi Gekirin - Ryugen Kiwi Arms' personal weapons
 * Trigger Magnum - Ryugen Double Arms' personal weapon
 * Lockseeds - Gives access to Budou's form changes, depending on which arm the lock is

Vehicles

 * Sakura Hurricane - Shared Rider Machine with Gaim
 * Rose Attacker - Ryugen's Rider Machine

List of Appearances

 * Kamen Rider Gaim
 * 1-10
 * Kamen Rider × Kamen Rider Gaim & Wizard: The Fateful Sengoku Movie Battle
 * Kamen Rider Gaim: Sengoku Battle Royale
 * Sengoku Movie Battle

Portrayal
Mitsuzane Kureshima is portrayed by Mahiro Takasugi (高杉 真宙).

As Kamen Rider Ryugen, his suit actor is Daisuke Satō (佐藤 太輔), who was previously the suit actor for Gokai Silver in Kaizoku Sentai Gokaiger and Beet J Stag/Stag Buster in Tokumei Sentai Go-Busters.