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Icon-build.png This article is about a/an rider in Kamen Rider Build.

―Night Rogue's transformation catchphrase.[src]

―Hell Bro's transformation catchphrase.[src]

"Everything...is for Namba Heavy Industries!"
―Personal catchphrase.[src]

"Where did I go wrong? I just...wanted to live a normal life...laughing at silly things...and crying with emotion. Don't become like me. Sento Kiryu."
―Utsumi's confession about his ideals his life[src]

"In that case, there's only one answer! I swear...my loyalty...to you!"
―Utsumi goes insane after the death of Namba and swears allegiance to Evolto.[src]

"I didn't do this to save you...but to protect...the Lost Bottle."
―Utsumi's final words after shielding Gentoku and Sawa from Evol's Steam blade.[src]

Nariaki Utsumi (内海 成彰 Utsumi Nariaki) is the former assistant of Gentoku Himuro at the Touto Institute of Advanced Matter Physics, and a devoted Namba Child who worked closely with Faust. After Gentoku's identity was nearly blown, Nariaki acted as the decoy Night Rogue (ナイトローグ Naito Rōgu) during Touto's raid into Faust and was gunned down by Gentoku, presumed dead in the aftermath of the attack.

He was, however saved by Evolto and converted into a cyborg in order to save his life. Surviving the attack, he began upgrading the Kaiser System for Seito and transformed into Hell Bro's (ヘルブロス Heru Burosu) for a test before giving it to Fu and Rai Washio. Shortly after, Evolto gave him a Evol-Driver, allowing him to transform into Kamen Rider MadRogue (仮面ライダーマッドローグ Kamen Raidā MaddoRōgu)[1]. From that point, Nariaki declared his allegiance to Evolto in a ruse to avenge Namba.


Utsumi is first seen reporting to Gentoku about Sento's application for a job at the Touto Institute of Advanced Matter Physics, noting that Sento had passed the entrance test with a perfect score.

Utsumi is Sento's direct superior at the Institute, reporting directly to the Prime Minister of Touto, Taizan Himuro, while at the same time also secretly assisting Gentoku/Night Rogue within Faust. He was one of the first present witnessing Taizan's collapse after the Pandora Box was stolen from the Institute. The Box was later hidden within a secret basement at one of Namba Heavy Industries' laboratories.

Faust's Pandora Box Plan

Shortly after the emergence of a second Kamen Rider, Utsumi was called upon by Juzaburo Namba for a favor. Later, as he watched Sento return to work despite it being a day off for all lab staff, Utsumi decided to reveal the location of the Box's hidden location to Sento. Though the Box ended up being reclaimed by Blood Stalk, and Utsumi was eventually forced to cooperate with Namba in his plan: to assume the identity of Night Rogue as a decoy in a staged operation by Touto to supposedly take down Faust. Due to Build's intervention, Utsumi was seemingly exposed as Faust's creator, though Build suspected that something was amiss.

Utsumi just before his "death".

Chased by Build to a bridge above a river, Utsumi, at his wits' end, confessed his inner troubles as a scientist. Revealing that he already knew that Build was Sento for a long time already, Utsumi urged Sento to not land into the same fate as his, and warned him to 'turn back' when he still have the time before he was shot in the shoulder by Gentoku, causing Utsumi to fall into the river below to his apparent demise.


Utsumi at Namba Heavy Industries.

"It's been a while...Himuro."
―Utsumi's first words upon meeting a former superior[src]

However, he barely survived the fall and was pulled out of the river by Blood Stalk, and later on, turned into a cyborg before being placed in the science division of Namba Heavy Industries. On the night of Kamen Rider Grease's arrival, Gentoku Himuro arrived at the Industries, waiting to talk to Juzaburo Namba until Utsumi approached him. The Golden Soldier

Utsumi was approached by Gentoku, who had been banished from Touto on his father's orders. Utsumi accepted Gentoku's request to be made into a Kamen Rider but not before taking pleasure in making him swallow his pride and beg for it. A Man Called Rogue

On Stalk's orders, Utsumi went to nascita where Sento Kiryu was surprised to see him alive as well as being able to make vastly superior coffee to Soichi Isurugi. Taking him underground, Utsumi revealed his intent to continue Sento's training to master the new Fullbottles left to him by Stalk in preparation for his deciding match against Kamen Rider Grease. Though Sento performed efficiently against simulated Smash Hazards with basic Best Matches, Utsumi pointed out that he would have to use the Hazard Trigger to defeat Grease. Sento understood this and had already designed blueprints for a device that would cancel his transformation if he went berserk. But it needed data of his Hazard Form's performance to complete it, to which Utsumi obliged by transforming into Night Rogue once more, using his self-made Transteam Gun from Gentoku's Blueprint. Though he overwhelmed by SmaphoWolf Hazard as Build went berserk, Utsumi was able to complete the dangerous procedure by using holographic Smashes to distract the rampaging Build, allowing him to forcefully pull out the Hazard Trigger and cancel Sento's transformation. With the data he needed to be collected, Sento was called away to intercept an attack on a Fullbottle facility. First Chapter

Working on behalf of Namba, Utsumi updated the Kaiser System originally developed by the late Kaisei Mogami to create Remocon and Engine Bro's, which would be used by soldiers of Seito, Namba's preferred choice to inherit Japan. Utsumi was given the personal thanks of Seito's Prime Minister Masakuni Mido. The Phantom of the West

Teaming Up with Evolto

As Evolto reaches the final phase of his plan (Phase 4/Black Hole), he openly declares to Namba that he'll now rule the world. Knowing this, Utsumi prepares for all-out war against Evolto, such as injecting Nebula Gas into the Washio brothers and even contacting his former boss to temporarily make an alliance.

However, Evolto was too strong to handle, even when Build, Rogue, Cross-Z and Remocon Bros teamed up. After Fu and Rai Washio, and Namba himself are killed, Evolto gives his last chance to Utsumi, making him choose whether he would fight to avenge Namba or fight for him.

Utsumi goes insane and preparing to break his benefactor's walking cane.

At this point, Utsumi finally goes insane. He renounced his connection with Namba by breaking his benefactor's walking cane and joining Evolto who, in return, gave Utsumi the second Evol Driver. Using the Bat and Engine Fullbottles, he became a Kamen Rider, whom Evolto christened as MadRogue.Mad World

Acting on behalf of Evolto, Utsumi appeared before Gentoku and Kazumi, who had been held in captivity by the Blood Tribe. Utsumi returned their Sclash Drivers, allowing them to transform and escape, but not before making them grovel for his assistance. Kamen Rider Build: Be The One


During Team Build's final battle against Evolto, Utsumi appears before Gentoku after he faced the clones of Engine and Remocon Bros. Transforming into MadRogue, Utsumi unexpectedly attacks Engine and Remocon Bros, showing his ruse against Evolto. Gentoku claims that he's indeed 'mad' and Utsumi calmly said that he's still a Namba Children at heart. They then form an alliance against Hell Bros.

Sawa later arrives with Pandora Box and gives MadRogue the Shark and Bike Fullbottles. MadRogue states that he implants a weakness against the clones, and using the Shark and Bike Fullbottles can neutralize their attacks, which they used to defeat the Hell Bros clone. However, Evol Cobra then arrives to collect the Purified Hammer Lost Fullbottle that he inject earlier to the Hell Bros clone.

Evol easily defeats both Rogues, until MadRogue activates the data he had collected from Evolto's Evol-Driver, dubbing them as 'Phases'. MadRogue then attacks Evol with super speed after he activates Phase 3, thus giving Evol a Hard time. But, after activating Phase 4, MadRogue stops all of sudden and receives a direct hit from Evol's punch, canceling his transformation.

The "death" of Utsumi.

Evol then explained that Utsumi could handle Evol's power since Utsumi wasn't totally human anymore. After Gentoku had shot him, Evolto turned him into a cyborg. Apparently, Phase 4 overloaded Utsumi's systems, hence why he suddenly stops. Evol then was about to kill both Gentoku and Sawa to obtain the Hammer Lost Fullbottle, but Utsumi manages to shield Evol's Steam Blade with his body, thus deactivating him as Evol throws Utsumi’s corpse away. Gentoku then successfully flees with Sawa, saving the Lost Fullbottle. His last words before dying implied that he was yet intended to save the world as he said "All for Namba" Zero Degree Flames

New World

Utsumi, working at the Namba Machine Workshop.

After Sento defeats Evolto for good, the new world had been successfully created. This world’s version of Utsumi is working at the Namba Machine Workshop and is shown making steel rebar. For some reason, Utsumi deems that the rebar is not up to standard and intends to break it using his knees, which he failed. The Tomorrow Build Will Create

As Utsumi originally used the Evol-Driver and was thus not injected with Nebula Gas, his memories from the original World of Build were not restored when Killbas used Ryuga Banjo to restore the Pandora Box using the white-colored Pandora Panel, despite his undying faith and loyalty for his boss Namba. Utsumi was seen in the Namba Machine Workshop, having finished working on his product, a steel walking cane known as the "Namba Stick" after countless failures. However, he breaks the cane after slamming it onto his knee, much to his shock. Build NEW WORLD: Kamen Rider Cross-Z

"Everything...is for Namba Heavy Industries...no, it's for the people. "
―MadRogue's one time catchphrase during his fight against Down Fall.[src]

Utsumi's appearance in NEW WORLD.

For some reasons, Utsumi regains fragments of his memories from the old world and he sought and asked Sento to douse him with Nebula Gas in order to regain all of his original world's memories. Due to Down Fall attacking Warehouse 3 and Sawatari Farm looking for the White Pandora Panel and Hazard Trigger, Utsumi was left soaked in the White Panel Nebula Chamber for a long period of time, only opened by Sento and remembered him. Sento then gave him an EvolDriver based on the original, but was modified for human use, which Utsumi later used to transform into MadRogue and helped his fellow riders in fighting against Down Fall. After Keiji Uraga's death, Utsumi, expressing his disdain for him being a cyborg in the old world, comically tries to break the Namba Stick cane again using his knees but ultimately fails, yet is amazed at its strength.Build NEW WORLD: Kamen Rider Grease


Utsumi typically shows a stoic demeanor to the people around him, silently following along Gentoku or Namba's orders. But as the series progressed, Utsumi is shown to be more maniacal than he appears to be. Throughout the series, Utsumi is shown to be very loyal to who he is working with, though it's later revealed that his true loyalty had always aligned with Namba Heavy Industries Ltd., as part of the Nanba Children. His affiliation with Gentoku is due to this as well since Gentoku was working for Namba at the time. Despite his absolute loyalty to Namba, Utsumi expressed interest in living a normal life as a normal scientist, though he felt it that dream was shattered the moment Gentoku shot him and Evolto turned him into a cyborg. Not wanting anyone to go through the same thing he went, he warned Sento not to follow the same path as him. In time, his cybernetic regeneration would develop a very maniacal and ruthless personality, as demonstrated when he forced Gentoku to kneel and stepped on his hand, resulting in sadistic laughter as he took his revenge for Gentoku's failed attempt to kill him. After Namba's death, his insanity took on a whole new level as he was even willing to pledge allegiance to Evolto in order to avenge Namba, and outright lashed out at Gentoku for turning him this way. However his allegiance to Evolto was actually false and only did so just to get close to Evolto and avenge Namba. This proves that Utsumi is a proficient liar and mastermind, and he is indeed as "Mad" as he looks.

Utsumi feeling exciting with his Evol-Driver.

During his tenure as Kamen Rider MadRogue, Utsumi became unnerved by deaths close to him and went overboard in his ambitions of creating his Namba Empire with the power of the Pandora Tower. However, Utsumi has no qualms resorting to underhanded methods himself, such has hostage taking and blackmail. Utsumi is also described to be a coward, but his ego is quickly inflated the moment he gains an upper hand. Utsumi was completely terrified when Gentoku attempted to rebel, but quickly regained his confidence after Gentoku was immobilized by his killswitch and violently attacked the unarmed Gentoku.

Upon his revival in the New World, Utsumi seemed to have retained the fragments of his memories and his habits from the old world, such as attempting to break metal canes. With Sento's help, he is able to fully regain his memories, he joined Team Build and is not hesitant to fight alongside the Riders against Down Fall. He also changed his catchphrase from "Glory to Namba" to "Glory to the people", indicating that he has really changed and became a hero.

Powers and Abilities


  • Artificially Enhanced Physiology: After Utsumi was injected with a certain amount of Nebula Gas, his physical condition was enhanced to a certain degree. To be noted that as his Hazard Level increase, his physical condition increase as well. It is implied by his use of the Transteam Gun that Utsumi has a high Hazard Level.​ He later uses the Evol-Driver, which usually requires a minimum Hazard Level of 5, which no ordinary human can accomplish. While possessing Utsumi's body, Evolto states that he had modified Utsumi's Evol-Driver for human use. This may mean that either Utsumi's Hazard Level was artificially enhanced, or his Evol-Driver required a lower Hazard Level. This reason can also be used when Sento creates a new Evol-Driver for him to use during their fight against Down Fall.

Former Powers

  • Cyborg Physiology: In order to save his life after he was shot by Gentoku and fell off the bridge, Utsumi was turned into a cyborg by Namba Industries. The extent of the abilities this grants him is unknown, but it may be what makes him able to emulate Evol's Phases. However, attempting to use Phase 4 caused him to overload. It may also be possible that Utsumi's cyborg nature is what allows him to use an Evol-Driver. After he was revived in the new world, even when his memories from the old world returned, his cyborg traits hasn't been carried over, which makes him return to being a human.


  • Gifted Intellect: Since Utsumi had worked for the Touto Institute, he possessed a certain level of intellect and this allows him to elevate to the rank of Gentoku's assistant. Because of this, Gentoku had speculated that Utsumi had a hand in the creation of Hokuto's Sclash Driver for Kamen Rider Grease, something which Sento Kiryu also suspected; this is later confirmed after Seito invades Hokuto, when it is revealed that Utsumi has built and upgraded another Sclash Driver for use by Kamen Rider Rogue, as well as duplicating Kaisei Mogami's Nebulasteam Gun for use by the Hell Bro's, all as part of Namba Heavy Industry's partnership with Seito. Utsumi also has access to data on some of Build's forms, including the Hazard and RabbitRabbit Forms, using them to Namba's advantage.


Night Rogue

Night Rogue

Night Rogue analyzing Build's SmaphoWolf Hazard Form.

"Bat! Mist Match! Bat! Bat-Ba-Bat! Fire!"
―Transformation announcement[src]
  • Height: 197.5 cm.
  • Weight: 103.0 kg.

Ability Perimeters:

  • Punching power: 17.2 t.
  • Kicking power: 20.5 t.
  • Maximum jump height: 49.0 m.
  • Maximum running speed: 100 m. per 4.1 sec.

Like Blood Stalk, Night Rogue's form is accessed with the Transteam Gun and the Bat Fullbottle.

Unlike Build, Night Rogue's Ability Perimeters are not spread out between his arms and legs. While Night Rogue gets power from only one Fullbottle, he's much stronger than Build's Trial Forms and his stats even surpass some of Build's Best Matches.

Utsumi's transformation into Night Rogue allows him to last for a good while against Build's Hazard Forms, at most before Build starts losing control. Utsumi, as Night Rogue, can also use his visor to analyze Build's stats.

Utsumi originally transformed into Night Rogue to act as Gentoku's decoy in order to keep his identity a secret. Later, he would use this form several more times in order to collect data on Sento while Gentoku was being experimented on in order to become Kamen Rider Rogue.

Night Rogue consists of the following parts:

  • Night Rogue Head (ナイトローグヘッド Naito Rōgu Heddo): Night Rogue's helmet.
    • Central Chimney (セントラルチムニー Sentoraru Chimunī): A chimney unit mounted on Night Rogue's head. It has a heat removal function, a function to disperse toxic gas, and can also launch special bullets.
    • NR Signal (NRシグナル NR Shigunaru): Data collection system in Night Rogue's helmet. It collects data in real-time and performs emergency repair on damaged parts of the suit. It also manages the condition of the body.
    • Bat Night Goggles (バットナイトゴーグル Batto Naito Gōguru): Transparent goggles to protect Night Rogue's face. The built-in ultrasonic sensor allows him to fight in complete darkness.
    • Night Seeker Eye (ナイトシーカーアイ Naito Shīkā Ai): Night Rogue's eyes. It has a built-in night vision sensor and can detect heat sources and movement.
    • Air Face Duct (エアフェイスダクト Ea Feisu Dakuto): A built-in gas mask in the helmet. It removes harmful substances from the air when breathing and can discharge toxic gases.
    • NR Face Guard (NRフェイスガード NR Feisu Gādo): Device that protects Night Rogue's head. In response to an enemy's physical attack, it emits a wave that cancels out the impact to nullify the damage.
  • Bat Chest Armor (バットチェストアーマー Batto Chesuto Āmā): Night Rogue's chest armor. The chest is equipped with a device called Steam Generator (スチームジェネレーター Suchīmu Jenerētā) that increases user's fighting ability. It can also accelerate the user's movement speed and attack power.
  • NR Unlimited Suit (NRアンリミテッドスーツ NR Anrimiteddo Sūtsu): Shock resistant bodysuit of Night Rogue. It can release the physical limiter and unleash the hidden physical ability of the user while offering protection from damage.
  • NR Steam Shoulder (NRスチームショルダー NR Suchīmu Shorudā): Night Rogue's shoulder armor. They optimize arm movement to improve attack accuracy. The steam pipes can also spray toxic gases while exhausting heat.
  • Dark Rush Arm (ダークラッシュアーム Dāku Rasshu Āmu): Night Rogue's arms. They increase speed and power, and can also use the attached Darkness Winger (ダークネスウィンガー Dākunesu U~ingā) blades to slash enemies.
  • NR Bat Glove (NRバットグローブ NR Batto Gurōbu): Night Rogue's gloves. They are reinforced and have sharp claws at the fingers to allow for slashing attacks.
  • Metal Knee Bat (メタルニーバット Metaru Nī Batto): Night Rogue's knee pads. They optimize leg movement to improve speed.
  • Dark Rush Leg (ダークラッシュレッグ Dāku Rasshu Reggu): Night Rogue's legs. They combine power and speed and specialize in high powered knees and continuous kicks.
  • Night Seeker Shoes (ナイトシーカーシューズ Naito Shīkā Shūzu): Night Rogue's shoes. They suppress sound for stealth attacks and can emit special steam for a kick attack.
Appearances: Build Episode 12, Raising the Hazard Level ~7 Best Matches~ ("First Chapter", "Final Chapter")

Hell Bro's

Hell Bro's

"Gear Engine! Gear Remocon! Funky Match! Fever! (Rhythmic beeping and engine revving) Perfect!"
―Transformation announcement[src]


  • Height: 202.0 cm.
  • Weight: 108.0 kg.

Ability Perimeters:

  • Punching Power: 41.6 t.
  • Kicking Power: 50.6 t.
  • Maximum Jump Height: 64.8 m.
  • Maximum Running Speed: 100 m. per 1.4 sec.

Hell Bro's is the fusion of the Kaisers Engine Bro's and Remocon Bro's, transformed into by inserting the Gear Engine or Gear Remocon into the Nebulasteam Gun, then removing it and inserting the other.

This form is exclusive to Kamen Rider Build: Raising the Hazard Level ~7 Best Matches~: Next Chapter.

Kamen Rider MadRogue

Kamen Rider MadRogue

"Kōmori! Hatsudōki! Evol Match! Are you ready? BatEngine! Fuhahahaha!"
―Transformation announcement[src]


  • Height: 196.0 cm.
  • Weight: 105.8 kg.

Ability Perimeters:

  • Punching Power: 43.5 t.
  • Kicking Power: 50.8 t.
  • Maximum Jump Height: 73.3 m.
  • Maximum Running Speed: 100 m. per 1.3 sec.

Utsumi transforms into Kamen Rider MadRogue by inserting the Bat and Engine Fullbottles into the Evol-Driver and turning the lever.

As MadRogue, Utsumi has higher punching and kicking power than Build's Rabbit Rabbit Form while also having a slightly lower running speed and jump height than its base perimeters. He is able to overwhelm Rogue and Grease in every area but is also easily outclassed by all of Evol's forms and Cross-Z Magma.

MadRogue's wings

After inputting Evol's data into his Driver, Utsumi was able to mimic his abilities up to Phase 3. In Phase 3 he demonstrated Evol's super-speed and energy covered punches, which allowed him to fight on par with Evol himself. Utsumi also attempted to use Phase 4, but his cybernetics overloaded before he was able to do so.

MadRogue wields the Nebulasteam Gun and Transteam Gun as his personal weapons and the Steam Blade as his sidearm. He is also able to wield any of Build's weapons if he inserts the corresponding Fullbottle into the Evol-Driver along with the Rider Evolbottle.

Kamen Rider MadRogue consists of the following parts:

  • MadRogue Head (マッドローグヘッド Maddorōgu Heddo): MadRogue's helmet.
    • Cybat Armor (サイバットアーマー Saibatto Āmā): Armored parts of MadRogue's head. It is explosion-proof, and will shield the user from explosions from the engines built into the armor.
    • MR Signal (MRシグナル MR shigunaru): Data collection system in MadRogue's helmet. It collects data in real-time, and performs emergency repair on damaged parts of the suit. It also manages the condition of the body. It can be fine-tuned by tracing the signal up and down.
    • Metal Bat Blade (メタルバットブレード Metaru Batto Burēdo): The bat-like crest on the helmet. It can establish a link with Hard Guardian and Clone Smash units to command them.
    • Mad Seeker Eye (マッドシーカーアイ Maddo Shīkā Ai): MadRogue's eyes. It has a built-in night vision sensor and can detect heat sources and movement. The built in ultrasonic sensor allows him to fight in complete darkness.
    • Air Face Duct (エアフェイスダクト Ea Feisu Dakuto): A built-in gas mask in the helmet. It removes harmful substances from the air when breathing and can discharge toxic gases.
    • MR Face Guard (MRフェイスガード MR Feisu Gādo): A device that protects Kamen Rider MadRogue's head. In response to an enemy's physical attack, it emits a wave that cancels out the impact to nullify the damage.
  • Cybat Armor (サイバットアーマー Saibatto Āmā): The purple and white armor on MadRogue. It is explosion-proof, and will shield the user from explosions from the engines built into the armor. The chest is equipped with a device called MR Steam Generator (MRスチームジェネレーター MR Suchīmu Jenerētā) that increases user's speed. The user can also deploy the Mad Night Flyer (マッドナイトフライヤー Maddo Naito Furaiyā) to fly.
  • MR Unlimited Suit (MRアンリミテッドスーツ MR Anrimiteddo Sūtsu): Shock resistant bodysuit of Kamen Rider MadRogue. It can release the physical limiter and unleash the hidden physical ability of the user while offering protection from damage. In addition, the special liquid that fills the inside of the suit can enhance the affinity between the special micro-body Mech Virus (メックヴァイラス Mekku Vu~airasu)} and the user.
  • Bad Steam Shoulder (バッドスチームショルダー Baddo Suchīmu Shorudā): MadRogue's shoulder armor. They maintain and manage the operating state of the internal combustion engine incorporated in each part of the suit by removing excess heat. They can also spray toxic gas using the components of the Fullbottle, develop a smoke screen, and launch special bullets.
  • High Burst Rush Arm (ハイバーストラッシュアーム Hai Bāsuto Rasshu Āmu): MadRogue's arms. The built-in engine and drive unit which are fueled by the components of the Fullbottles significantly increase the strength and speed of movement in the arms.
  • Night Raid Edge (ナイトレイドエッジ Naito Reido Ejji): The blades on MadRogue's arms. The sharpness of the blade increases the darker the area is. A blow in complete darkness is instantly fatal.
  • Mad Vengeance Glove (マッドヴェンジェンスグローブ Maddo Vu~enjensu Gurōbu): MadRogue's gloves. They are reinforced, and have sharp claws at the fingers to allow for slashing attacks. The power of the attacks increases the more the user hate the enemy.
  • High Burst Rush Leg (ハイバーストラッシュレッグ Hai Bāsuto Rasshu Reggu): MadRogue's legs. The built-in engine and drive unit which are fueled by the components of the Fullbottles significantly increase the strength and speed of movement in the legs.
  • Mad Vengeance Shoes (マッドヴェンジェンスシューズ Maddo Vu~enjensu Shūzu): MadRogue's shoes. They are reinforced, and have a sharp claw at the sole that can inject a powerful neurotoxin. The power of the attacks increases the more the user hate the enemy.

This form has two finisher:

  • Evol Driver Finishers:
    • Evoltic Attack (エボルテックアタック Eborutekku Atakku): This finisher has six variations:
      • MadRogue flies into the air with the Mad Night Flyers and rams into the enemy.
      • MadRouge leaps into the air and sprouts the Mad Night Flyers before delivering a flying dropkick to the enemy.
      • MadRogue performs a low kick covered in purple energy to an enemy on the ground.
      • MadRogue fires a steam projectile covered in purple energy from the Nebulasteam Rifle.
      • MadRogues unleashes two energy slashes from the Steam Blade that travel through the air and follows them up with sustained fire from the Nebulasteam Gun.
      • After replacing the Engine Fullbottle with the Bike Fullbotle and initiating the Evoltic Attack, MadRogue summons the Machine Builder, which redirects the enemy's attacks by binding them to it's front wheel before ramming into the enemy.
  • Evol Driver + Kaizoku Hassyar Finisher:
    • Pirate Finish/Kaizoku Densya: MadRogue inserts the Kaizoku Fullbottle and Rider System EvolBottle into the Evol Driver and turns the crank, summoning the Kaizoku Hassyar. He then charges the weapon by pulling the arrow and holds it for a period of time before letting it go. The weapon then fires a green and azure energy train that rams into the enemy several times.
Appearances: Build Episodes 38-40, 42, 44-45, 47, Build NEW WORLD: Kamen Rider Grease



  • Transteam Gun - Night Rogue's transformation device and personal weapon
  • Fullbottles - Night Rogue and MadRogue's transformation trinkets
  • Nebulasteam Gun - Hell Bro's transformation device and MadRogue's personal weapon
  • Gears - Hell Bro's transformation trinkets
  • Evol-Driver - MadRogue's transformation device


  • Steam Blade - Standard sidearm weapon. Can combine with the Transteam Gun to form the Steam Rifle or the Nebulasteam Gun to form the Nebulasteam Rifle.
  • Kaizoku Hassyar - MadRogue's weapon granted by the Kaizoku Fullbottle.

Other Equipment

Legend Rider Devices

"(Digital beeping) MadRogue!"
―Activation announcement[src]

"The bat rider with the feeling of revenge is...MadRogue! (復讐の思いを秘めた蝙蝠ライダーは...マッドローグだ! Fukushū no omoi o himeta koumori Raidā wa... MaddoRōgu da!)"
―Secondary activation announcement[src]

"(Right-hand Ridewatch's announcement)! Armor Time! (Evol-Driver Trial Form orchestra with post lever-crank noise) Evol-Match! MadRogue!"
―Transformation announcement in the Ziku-Driver's left-hand slot[src]

"Finish Time! Evoltic Time (Break/Burst)!"
―Finisher announcement in left-hand slot[src]

MadRogue Ridewatch (マッドローグライドウォッチ Maddo Rōgu Raidowotchi): Based on Kamen Rider MadRogue, this Ridewatch would provide access to the MadRogueArmor. It is dated 2017.



  • Namba Heavy Industries/Faust
    • Juzaburo Namba: Utsumi shows to be very loyal to him, even after Evolto kills Namba.
  • Team Build
    • Sento Kiryu/Katsuragi Takumi: Both are scientists but were used by Gentoku to start the war. While working for Utsumi, Sento can't help but compares Utsumi's stoic personality being akin of a Cyborg, which was ironically proven true by Evolto himself. In the New World, he later joins forces with Sento and Team Build against Down Fall.
    • Ryuga Banjo: Utsumi saw Banjo as an enemy. Later, they are allies in the New World.
    • Kazumi Sawatari: He had victimized his friends in Hokuto forcing him to give him the Pandora's Box in exchange for his own freedom. Later, they became allies in the New World.
    • Gentoku Himuro: Formerly his superior in Touto, Gentoku shot Utsumi as a way of covering his tracks. But he somehow returned and revealed that ever since he was saved by Evolto, he now working for Namba until his chairman's/president's death at Evolto's hands. Gentoku thought that he was responsible for Utsumi's dissension to madness as MadRogue. Although after Utsumi ruse was discovered, they become somewhat uneasy allies until Evolto kills Utsumi. Later they became allies in the New World, though, Utsumi still appears to express disdain for him being a cyborg caused by Gentoku in the previous world.
    • Misora Isurugi: So far, Utsumi and Misora only met each other once, and not in a good light as Utsumi forcefully grabbed the completed Evol Driver from her, while she was distracted seeing her father as Blood Stalk. Later they became allies in the New World.
    • Sawa Takigawa: She and Utsumi were both Namba Children. But despite her joining Team Build permanently, he called Sawa by the phone letting her know of his plans in destroying Evolto from the inside, showing their somewhat mutual trust to each other. Later they became allies in the New World.
  • Shinobu Katsuragi: Worked alongside him with Evolto until his true agenda was revealed.


  • Evolto: Served under him gaining the power to become Kamen Rider MadRogue, until revealing his plan to destroy him from the inside.

Behind the Scenes


Nariaki Utsumi is portrayed by Yuki Ochi (越智友己 Ochi Yūki). As Night Rogue, his suit actor is Jun Watanabe (渡辺淳 Watanabe Jun). As Kamen Rider MadRogue, his suit actor is Yuji Nakata (中田 裕士 Nakata Yūji).


The ending scene in episode 38, where Utsumi snapped Namba's cane after feigning insanity has been made into a meme which involves parodying said scene into various situations. In the Japanese fandom, this is labelled under the Twitter hashtag Nariaki Utsumi Darn Collaboration Grand Prix (内海成彰クソコラグランプリ Utsumi Nariaki Kuso Kora Guranpuri). Kouhei Takeda (Kazumi Sawatari) and Eiji Akaso (Ryuga Banjo) has also recreated this scene on Yukari Taki's (Sawa Takigawa's) Twitter page, and Instagram story.


Sento's depiction of "cyborg Utsumi".

MadRogue with a Snap Ride Builder



Icon-build.png Kamen Rider Build
Kamen Riders
Sento Kiryu (Takumi Katsuragi) - Ryuga Banjo - Kazumi Sawatari - Gentoku Himuro - Evolto - Nariaki Utsumi - Shinobu Katsuragi
Movie-exclusive: Kengo Ino - Killbus - Keiji Uraga
Drivers/Transformation Gear
Build Driver - Transteam Gun - Nebulasteam Gun - Sclash Driver - Evol-Driver
Transformation Devices
Fullbottles - (Great) Cross-Z Dragon - Sclashjellies - Hazard Trigger - Cross-Z Magma Knuckle - Evol-Trigger - Grease Blizzard Knuckle - Killbuspider - Grease Perfect Kingdom
Drill Crusher - Hawk Gatlinger - 4Koma Ninpoutou - Kaizoku Hassyar - Fullbottle Buster - Steam Blade - Beat Closer - Twin Breaker - Muscle Glove - Solstall Wings - Giant Scratcher - Space Ride Arm - Spine Knuckle - Long Range Cleaner - Trash Converter - Gold Lio Gauntlet - Multi Deluge Gun
Pandora Box - Halfbodies - Fullbottle Holder - Build Phone
Vortex Finish - Hazard Level - Project Build - Sky Wall - Nebula Gas
nascita: Misora Isurugi - Soichi Isurugi - Sawa Takigawa - Kazumi Sawatari - Gentoku Himuro
Kamen Riders: Eiji Hino - Gentaro Kisaragi - Kouta Kazuraba - Takeru Tenkuji - Emu Hojo - Hiiro Kagami - Taiga Hanaya - Kiriya Kujo - Kuroto Dan - Parado - Sougo Tokiwa - Geiz Myokoin - Tsukuyomi
Prime Ministers: Taizan Himuro (Touto) - Yoshiko Tajimi (Hokuto) - Masakuni Mido (Seito)
Namba Heavy Industries Ltd.: Juzaburo Namba - Nariaki Utsumi - Haruhiko Wanibuchi - Guardian
Hell Bro's: Fu Washio - Rai Washio - Yoshikazu Takahashi - Norio Matsui
Aliens: Vernage
Gentoku Himuro - Evolto - Nariaki Utsumi - Takumi Katsuragi - Shingo Kuwata - Eita Kawai - Yoshikazu Takahashi - Norio Matsui
Normal Smash: Fang Smash - Needle Smash - Strong Smash - Burn Smash - Flying Smash - Mirage Smash - Square Smash - Press Smash - Ice Smash - Stretch Smash
Empowered Smash: Strong Smash Hazard - Press Smash Hazard - Stretch Smash Hazard - Flying Smash Hazard
Hard/Hazard Smash: Castle Hard/Hazard Smash - Stag Hard/Hazard Smash - Owl Hard/Hazard Smash
Clone Smash: Press Clone Smash - Stretch Clone Smash - Strong Clone Smash - Flying Clone Smash
Lost Smash: Owl Lost Smash - Stag Lost Smash - Castle Lost Smash - CD Lost Smash - Scissors Lost Smash - Zebra Lost Smash
Foundation X
Kaisers: Kaisei Mogami (World of Build, World of Ex-Aid) - Nebula Bugster
Blood Tribe
Kengo Ino - Ryoka Saiga - Mitsuomi Gobara - Evolto - Killbus - Akaba (imitation) - Aoba (imitation) - Kiba (imitation) - Remocon Bro's (imitation) - Engine Bro's (imitation)
Down Fall
Keiji Uraga - Simon Marcus (Phantom Crusher)