Mitsuzane Kureshima

"If you'd had the guts to make the tough decisions, you could have been the hero humanity needed. That's why I admired you. That's why I thought you deserved Mai! But you've been twisted by the lies you called "hope". Your sweet optimism blinds you to reality, and forces you to make stupid mistakes over and over. Hope is a dangerous disease, and a contagious one at that. And you Kouta.. have been spreading it like a plague!"

- Mitsuzane revealing his darkside to Kouta for the first time.

Mitsuzane "Mitchy" Kureshima (呉島 "ミッチ" 光実) is Kamen Rider Ryugen (仮面ライダー龍玄 [リュウゲン]). He later becomes the second Kamen Rider Zangetsu Shin (仮面ライダー斬月 真 [ザンゲツ シン]), supposedly succeeding his older brother Takatora as a protector of humanity. However he seems to have his own dark agenda, which greatly involves his former friend, Kouta Kazuraba.

Beat Riders Saga
After Kouta's near death encounter with Armored Rider Zangetsu forces him to quit, Mitsuzane goes to Drupers and convinces Sid to give him a Sengoku Driver. From there, Mitsuzane becomes Team Gaim's second Armored Rider, the Chinese warrior-themed Kamen Rider Ryugen. After learning that the white Armored Rider, Zangetsu, is his brother Takatora, Mitsuzane resolves to uncover the truth behind the Yggdrasill Corporation's ties to Helheim Forest.

Yggdrasill Saga
However, learning of Yuya's fate prior with the intention of keeping Kouta in the dark about it, Mitsuzane renounces his earlier intent to expose his family's company upon being shown the ruins within Helheim Forest. Supporting the Yggdrasill Corporation in secret, Mistuzane maintains his appearance as a Beat Rider, going his own way to protect Kouta and Mai. Though he answers to Ryoma Sengoku, Mitsuzane learns that the scientist and his group are acting on their own agenda. Like his brother, Takatora, Mitsuzane is smart and revealed to be quite a manipulator with a desire to make sure Mai would live in blissful ignorance.

Helheim & Overlord Saga
"Kouta Kazuraba. He crossed the line he shouldn't have crossed. He's my enemy now, nothing more and nothing less."

- Mitsuzane explaining to Sid of his hatred toward Kouta.

While initially admiring Kouta for his earnestness, Mitsuzane gradually finds Kouta's ideals and methods disagreeable, eventually become disillusioned with his friend after he tells Mai everything of the Inves and Yggdrasill's conspiracy. Combined with being slapped by Mai after taking his frustrations on Kouta for making her sad, an unhinged Mitsuzane plots to get rid of Kouta within Helheim Forest, so much so that he is willing to attack Kouta when his friend lowers his guard and kill him.

His plot is foiled by the interference of Kaito who, despite not caring much about what is going on between Kouta and Mitsuzane, cannot stand such cowardly acts. Mitsuzane follows his brother and Ryoma's group into the forest intent on stopping the Over Lords, however, Takatora is ambushed by his own group and is thrown off a cliff. Mitsuzane ignores his brother's pleas to work with Kouta to save humanity and uses his brother's Genesis Driver to instigate betrayal to Kouta. However he is intercepted by Kaito.

Mitsuzane is not as physically strong as his brother, despite the power given by the Genesis Driver. Instead, Mitsuzane uses the increased power and resorts to cheap tactics to fight as shown using the debris and junk off the abandoned construction site to his advantage and then calling Inves when he can't win.

After escaping from an enraged Kachidoki Arms Gaim and Lemon Energy Arms Baron, he watches them from a safe distance as he turns off his transformation, revealing that he is now the new Zangetsu Shin.

At Drupers, Mitsuzane is surprised to hear that Mai agrees to work there for free. Yoko then enters and asks both him and Kouta to come to Yggdrasill. There together with Kaito they hear from Ryoma that Sid betrayed Yggdrasill to seek the Forbidden Fruit from the Over Lords. After planning to find Sid in a separate way, Ryugen discovers where Sid is hiding. Rather than being enemies, they ally together and plan to kill Kouta and Kaito as Mitsuzane sets a trap into calling Gaim in Jimber Peach Arms for help as Ryugen in safe distance, then as Zangetsu Shin before Gaim arrives to find him, attempting to attack Gaim. However, he is easily defeated by Gaim Jimber Lemon Arms until they were interrupted by Demushu, with four Riders in a battle royale for the Over Lord until Demushu's escape through a sudden appearance of a Crack, leading Gaim and Baron to follow while Sigurd and Zangetsu Shin-suited Mitsuzane are confronted by Redyue, who after a brief skirmish gives up and tells them to follow where the Forbidden Fruit is.

Already aware of Redyue's trap after she suddenly gave up herself, Mitsuzane knows that Redyue has been planning behind their back, as well as Rosyuo's, to obtain the Forbidden Fruit for her own, with Redyue taking an interest in his dark side after Sid left for the fruit in the possession of Rosyuo and got himself killed.

Redyue gives Mitsuzane Sid's hat, with Mitsuzane unaware that Redyue has seen his brother alive. He leads an Inves army with Redyue and other Over Lord class Inves as they enter the real world.

Forbidden Fruit Saga
He tries to kill Gaim until Bravo arrives, as his fighting style behind Zangetsu Shin's suit cannot be fooled by Oren, leaving Mitsuzane speechless when Gaim demands him to reveal his identity. However, he manages to escape from Gaim as he uses Dyudyuonshu as a shield to block his attack, so his identity is not revealed. With all of his plans to manipulate events and eliminate Kouta ending up in failure and Kouta getting stronger, Mitsuzane becomes much more insane than ever before. He believes he can still win against Kouta as his former friend is "stupid and simple" and the power of Kiwami Arms he now possesses is only a fluke. Once the time comes, he can find a way to kill him and have him out of the way for good.

Visiting Team Gaim's garage, his friends were relieve that Mitsuzane was alright, however Kaito and Yoko suspect that he's still hiding something. He then talked to Yoko as he reveals to her that he's working with one of the Over Lords to obtain the Forbidden Fruit. However, Yoko refuses the offer as she has no interest of obtaining the fruit for herself, but instead of a perfect leader to guide. She even told Mitsuzane that he has no home, due to his actions. Returning to Yggdrasill Tower, Mitsuzane was furious about Redyue making her announcement as he started to lose faith in the Over Lord. Sometime later, in his brother's office, watching the scene from the tower, and seeing that humanity has no chance of defeating the Over Lords, a hopeless Mitsuzane reaffirms his belief that aligning himself with the Over Lords was his best choice.

Later, Mitsuzane wants his teammates to join him with the Over Lord as they started to suspect that he's acting strange. He went to Mai as Mitsuzane was furious that she would take Kouta's side, however she told him that she wants hope as she doesn't want Kouta to bear the situation alone, which leaves Mitsuzane unsatisfied. Mitsuzane decides to get Kouta from Drupers as he reveals to him that Kouta and his "hope" was something he once looked up to and believed that his unwavering will was why he thought Mai was best for Kouta. However, Mitsuzane tells him that it's nothing more than sweet optimism and that his naiveté has been taking their friends away from him. In a fit of rage, he transforms and reveals that he is the imposter Zangetsu Shin, attacking Kouta, who responds by transforming. Mitsuzane defeats Kouta, but Takatora appears from surprise, and lectures Mitsuzane about why he has become this person. With Kaito and Redyue appearing, and Kaito knocked down, Mitsuzane and Redyue disappear.

That night, Mitsuzane sits down and has a lengthy conversation with Redyue if she has a family. The Over Lord revealed that she does, however her family were the first to be killed by her for entertainment, seeing that it would interesting if someone kills their family. He deeply thinks about what he did to Kouta and his older brother. He then receives a message from Takatora, who challenged him to a duel. The two arrive at the battlefield and say their final words before transforming and engaging in their duel. Despite having stronger gear, Mitsuzane is losing to his brother's skill. Mitsuzane plays dirty, but Takatora overcomes it and has a chance to kill Mitzuzane before he hesitates. Mitsuzane shatters Zangetsu's mask, and Takatora slowly falls into the sea.

Mitsuzane is haunted by his brother's "spirit", getting vivid hallucinations that he is there despite knowing that he defeated him already in their previous encounter. Mitsuzane kidnaps Mai by injuring Peko and later fights Kouta and Kaito. In this encounter, Mitsuzane is shown to be more capable than his fighting style as Zangetsu Shin, defeating the undefeated Kachidoki Arms single handedly and even injuring a Kiwami Arms Gaim and Lemon Energy Arms Baron alone without assistance from Redyue. Mitsuzane takes Mai to the Helheim Forest where the machine to revive the Over Lord Queen is.

The Golden Fruit Cup Event
Set sometime in the future, this Mitsuzane is the same Mitsuzane as in the main world, somehow retaining his memories of defeating his brother. Feeling regret of his main world counterpart's sins, he has no intention of killing Kouta or defeating his brother again. When Kouta is brainwashed into Kouta-Yami. Mitsuzane steps up to the field to stop his long-time friend, successfully allowing Lapis to enter Kouta's mind to stop him. Mitsuzane teams up with most of the other Riders to stop Armored Rider Mars.

Personality
He is initially a member of Team Gaim and Kouta 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 to him being able to be himself while there.

He also respected Kouta once as a role model in the early stages of the show, basing his own beliefs around Kouta'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 Kouta being shaken to the core after the encounter with Zangetsu. After knowing that Yuya Sumii turned into Byakko Inves and for Kouta as Gaim unknowingly killed him, Mitsuzane tried to hide this from Kouta and even Team Gaim, trying not to disappoint his friends.

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 Kouta the Suika Lockseed. Mitsuzane also stole the Suika Lockseed from his brother without any guilt and swears to betray anyone or everything as long he can retain his friends' happiness. He also tries to destroy Kouta after he learned that Mai likes Kouta more than himself. A majority of Yggdrasill know about Mitsuzane's inner darker personality. Alongside this, Kaito and Redyue are also aware of this sinister personality. As a result of failing to kill Kouta and attempting to manipulate other people's lives, Mitsuzane has been driven into insanity blaming Kouta for ruining his perfect image of the world.

Upon witnessing Rosyuo's power when he destroyed the missiles that were launched by the government, he becomes even more insane, believing that he has made the right choice in siding with the Over Lords. His mindset is that when the human race is destroyed, he would finally be able to do whatever he wants without anyone getting in his way. His dark nature was then finally exposed to the Beat Riders resistance and later Takatora and Kouta.

In his battle as Zangetsu Shin, Mitsuzane was seen able to use almost anything in his advantage, for example throwing garbages and other objects (eg. sands for smokescreen) to keep the opponent busy, summoning Inves when outmatched similar to Kaito in his days as a Beat Rider, killing his own ally as an escape and even taking advantage of the opponents' weakness (eg. Kouta's naiveté and Takatora's empathy for him).

However, despite being a villain now, Mitsuzane still cares for his teammates (all except for Kouta). As shown, when Rat and Rica were kidnapped by Redyue's Inves, he saved them and brought them to a safe place. He also tries to get Mai on his side so she would be safe around him.

Arms
Like with the other Armored Riders and New Generation Riders, Kamen Rider Ryugen/Zangetsu Shin's forms are called Arms (アームズ). As Ryugen, all of his Chinese Soldier-themed Arms' helmets share the suffix Men (面) as their title, while his visors are called Ryugan (龍眼).

Devices

 * Transformation devices:
 * Sengoku Driver - As Ryugen
 * Genesis Driver - As Zangetsu Shin
 * Lockseeds - Gives access to Ryugen/Zangetsu Shin's Arms changes, depending on which lock is used

Weapons

 * Arms Weapons - Weapons that come with the Arms:
 * Ryugen:
 * Budou Ryuhou - Ryugen Budou Arms' personal weapon
 * Kiwi Gekirin - Ryugen Kiwi Arms' personal weapons
 * Trigger Magnum - Ryugen Double Arms' personal weapon
 * Melon Defender - Ryugen Melon Arms' personal weapon
 * Banaspear - Ryugen Banana Arms' personal weapon
 * Pine Iron - Ryugen Pine Arms' personal weapon
 * Zangetsu Shin:
 * Sonic Arrow - Zangetsu Shin Melon Energy Arms' personal weapon

Vehicles

 * Lock Vehicles - Vehicles that unfold from special Lockseeds:
 * Sakura Hurricane - Borrowed Rider Machine from Gaim
 * Rose Attacker - Ryugen's Rider Machine

List of Appearances

 * Kamen Rider Gaim
 * 1-36, 38
 * Kamen Rider × Kamen Rider Gaim & Wizard: The Fateful Sengoku Movie Battle
 * Kamen Rider Gaim: Sengoku Battle Royale
 * Sengoku Movie Battle
 * Heisei Rider vs. Showa Rider: Kamen Rider Taisen feat. Super Sentai
 * Ressha Sentai ToQger Vs. Kamen Rider Gaim Spring Vacation Combining Special
 * Kamen Rider Gaim the Movie: The Great Soccer Match! The Golden Fruit Cup!

Portrayal
Mitsuzane Kureshima is portrayed by Mahiro Takasugi (高杉 真宙). He was also a guest star in Episode 10 of Garo: Yami wo Terasu Mono.

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.

Legend Rider Lockseeds

 * The following Legend Rider Lockseeds are styled for Ryugen:
 * V3 - "Chikara, Waza, Double Typhoon!"
 * Skyrider - "Sky, Henshin, Sail-ing Jump!"
 * Super-1 - "Seki, Shin, Sho-rin Ken!"
 * Kuuga - "Chō Henshin, Ha-Ha-Ha!"
 * Double - "Cyclone, Joker, Ha-Ha-Ha!"
 * Double CycloneJokerXtreme - "Cyclone, Joker, Xtreme!"
 * Joker - "Joker, Kirifuda, Sei-ya Ha!"
 * Meteor - "Hwacha, Ha-Ha-Ha!"