Mitsuzane Kureshima

"Kota, use this!"

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

Mitsuzane Kureshima (呉島 光実), nicknamed Mitch (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 transform into Ryugen, he defeated Hideyasu's Inves as he gain a new Lockseed from him. Sometimes later, he had a dream that the mysterious girl tells him about the fate using the Sengoku Driver. On the next day, Mitsuzane discuss to 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 arrive to challenge Mitsuzane to test his strength. He transform into Ryugen as Baron summons 2 Inves, which one of them is on 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 throw the Ichigo Lockseed to Gaim, which change him into Ichigo Arms. With the new form, Gaim and Ryugen finishes off the two Inves. until Ryoji and Hideyasu appears and transform into Armored Riders Kurokage and Guridon respectively, which shock Gaim, Ryugen and the members of Team Gaim.

Bravo and Suika
After they transform into Guridon 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
While examine to Suika Lockseed, Mitsuzane exams the Lockseed that is now unresponsive as it changed colors somehow. When Mai gone missing, both Mitsuzane and Kota got a call same time until Kota witness the plants from the Helheim Forest, which was told from before to Mitsuzane and goes to rescue Mai. Mitsuzane then got a call from his teammate that Sid appears 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 to 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 arrived in time finding Mai protected by Baron from a Dragon Inves and assist him, as well as find an escape portal before it's closing. With the Riders managed to escape the forest with Inves follows 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 when Gaim transformed into Pine Arms and had the Inves finished with the combination of Pine and Mango finishers. When being told by Mai about why Kaito's attitude looks like a jerk in search for power, Kota and Mitsuzane soon feel sorry for him about his dark past. 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, failed as it wasn't their problems. Before Mitsuzane enters home at night, he look at the Suika Lockseed he hold now changed color back and respond again, then hide it from his brother noticed it. When Takatora arrived, he told Mitsuzane to make sure the gate was locked since a Beat Rider broke in a stole something. Takatora then ask Mitsuzane about his opion on Beat Riders. In the morning, Mitsuzane arranged a meeting to search a the plant from Helheim that was 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, but Lockseed, which gives Mitsuzane an idea to bait the Inves out once he and Kota head back to Helheim to find a pre-matured Lockseed, before Mitsuzane brought a plastic. Knowing the Inves would eat a matured Lockseed may transformed into a massive form, according to Mitsuzane, the Lockseed transformation into matured can only be picked by those who wears a Sengoku Driver, so Mitsuzane gave his belt and Budou Lockseed to Gaim to pick the pre-matured Lockseed and insert it to plastic. While baiting the Inves out, their plan are shortly interruped by an annoying old lady whom Gaim scared, 3 kids, and the pack of crows until the Inves arrived in a few minutes and had a chance to attack it. Before the Inves escape, Ryugen attach a tracking device where the Inves currently is. Once Kota and Mitsuzane arrived at a factory where the Inves is, they witness a full of plants appeared around the factory and one victim was killed by it. With the Inves arrived, Mitsuzane and Kota fight back as they be able to finished the Inves. Once the high leveled Inves is finished, Kota and Mitsuzane hides and finds out there are more Elementary Inves to come 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, as seen with the belt's faceplate. Kota snaps Mitsuzane out before it almost burned them, they managed to escape the factory without being spotted and got themselves burned.

Upon entering the Helheim, 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 (who is his brother), upon getting killed, he is saved by a sudden appearance of Kurokage. Upon Kurokage's belt is accidently destroyed, Zangetsu got call that the Inves attacks his scientists, which is also that Mitch soon hear his brother's name of being the white Rider to be true, especially when he saw his brother's belt faceplate. Upon in a ruin place where the scientist were, he found a multiple Lockseeds and took them all evidence for Sid. As a promise, he and his team won't be in a so-called Inves Game and rather sticked with hunting the escaped Inves. Team Gaim soon celebrates a Christmas Day as a victory.

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 Yggdrasil 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 has a cheerful and optimistic personality, in reality, Mitch 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 Mitch tells Sid that one day he will surpassed his brother. Mitch also forced Sid to give him a Lockvehicle or else Mitch will tell Takatora that Sid is the one who gives Kota the Suika Lockseed. Mitch also stole the Suika Lockseed from his brother without any guilt. Currently, only Sid who knows Mitch's inner darker personality.

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

Devices

 * Sengoku Driver - Transformation device
 * Lockseed-exclusive 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

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.