This article is about a/an weapon/transformation device in Kamen Rider Build.

"Gear (name)!"
―Gear insertion announcement[src]

―Crocodile Crack Fullbottle insertion announcement[src]

"Lost Match!"
―Fullbottle without Best Match insertion announcement[src]

―Other Fullbottle insertion announcement[src]

"Funky! (Rock music, engine revving) Engine Running Gear!"
―Engine Bro's/Kaiser Reverse transformation announcement[src]

"Funky! (Slow rock music, rhythmic beeping) Remote Control Gear!"
―Remocon Bro's/Kaiser transformation announcement[src]

"Gear Engine! Gear Remocon! Funky Match! Fever! (Techno music, rhythmic beeping, engine revving) Perfect!"
―Hell Bro's/Bi-Kaiser transformation announcement[src]

"Funky Drive! (Gear name)!"
―Finisher announcement with any Gear [src]

"Funky Finish!"
―Hell Bro's finisher announcement[src]

"Funky Break! Crocodile! (Scream)"
―Finisher announcement with the Crocodile Crack Fullbottle[src]

"Funky Attack! (Lost Match/Fullbottle)!"
―Finisher announcement with any Fullbottle[src]

"Rifle Mode! Funky!"
―Combination with Steam Blade announcement[src]

"Funky Shot! (Gear name/Lost Match/Fullbottle)!"
―Rifle Mode finisher announcement with any Gear or Fullbottle[src]

"Funky Shot! Crocodile! (Scream)"
―Rifle Mode finisher announcement with the Crocodile Crack Fullbottle[src]

The Driving Scale Smoke Pistol Nebulasteam Gun (駆鱗煙銃 ネビュラスチームガン Kuroko Enjū Nebyura Suchīmu Gan) is the transformation device and personal weapon of the Kaisers, as well as the personal weapon of Kamen Rider Rogue and Kamen Rider MadRogue. It combines with the Steam Blade to form the Nebulasteam Rifle (ネビュラスチームライフル Nebyura Suchīmu Raifuru).

The Nebulasteam Gun is a creation of Kaisei Mogami, based on experiments mixing Nebula Gas with the Bugster Virus. It is the core of the Kaiser System (カイザーシステム Kaizā Shisutemu). Takumi Katsuragi, who at the time was Mogami's supervisor, would later create a simplified and weaker version of the device called the Transteam Gun[1]. Nariaki Utsumi would eventually update the Kaiser system for the use of Namba Heavy Industries Ltd.


The Nebulasteam Gun is composed of the following parts: [2]

  • Gear Bottle Slot (ギアボトルスロット Gia Botoru Surotto) - The slot of the Nebulasteam Gun, it takes in a Fullbottle for transformation or an attack. It has a function which activates the Transgel Solid inside of the Fullbottle via a special pulse, allowing the Nebulasteam Gun to suck up the Fullbottle's essence.
  • Blazing Steamer (ブレイジングスチーマー Bureijingu Suchīmā) - The muzzle of the Nebulasteam Gun, it can shoot out bullets wrapped in hot steam called Steam Burettes (スチームビュレット Suchīmu Byuretto) (On a side note, a Burette is a lab equipment used in chemistry to measure the volume of a liquid or gas. It consists of a glass tube with a stopcock at one end). Additionally, it also shoots out Transgel Steam (トランジェルスチーム Toranjeru Suchīmu), which is used for transformation.
  • Mystic Charger (ミスティックチャージャー Misutikku Chājā) - The golden panel on the Nebulasteam Gun with turquoise gears on it. It is a steam generation unit which is directly mounted onto the gun. It heats up the inserted Fullbottle/Gear Bottle's Transgel Solid (essence) and turns it into Transgel Steam, allowing transformation. In addition, Nebula Gas is also stored inside of its inner tank.
  • Funky Trigger (ファンキートリガー Fankī Torigā) - The trigger used to transform or shoot. Pulling the trigger activates the Nebulasteam Gun's internal units to allow transformation, shooting or special deathblows.
  • Power Hit Grip (パワーヒットグリップ Pawā Hitto Gurippu) - The hilt of the Nebulasteam Gun. Because it is composed of materials that can withstand impacts, it can be used as an impromptu striking weapon. Additionally, a computer unit inside it uses combat data to figure out the user's combat style and adjusts shooting behaviour accordingly.

Users (chronological order)

User Kamen Rider/Kaiser Episode Obtained Description
Kaisei Mogami
Kamen Rider Heisei Generations FINAL: Build & Ex-Aid with Legend Riders (Pre-series) Creator of the original Nebulasteam Gun.
Kaisei Mogami (World of Ex-Aid)
Kaiser Reverse
Kamen Rider Heisei Generations FINAL: Build & Ex-Aid with Legend Riders (Pre-series) Presumably given a Nebulasteam Gun by his World of Build counterpart.
Nariaki Utsumi
Hell Bro's/Kamen Rider MadRogue
Kamen Rider Build: Raising the Hazard Level ~7 Best Matches~: Next Chapter

Using Kaisei Mogami's research, Utsumi created his own Nebulasteam Gun and began revising the Kaiser system. After recovering the Nebulasteam Gun from Nebula Hell Bro's, Utsumi completed his new Kaiser system and tested it, transforming into Hell Bro's. This Nebulasteam Gun would later be given to the Clone Hell Bro's before being returned to Utsumi. Utsumi would later use his Nebulasteam Gun as his personal weapon after becoming Kamen Rider MadRogue.

Unnamed man
Nebula Hell Bro's
Kamen Rider Build: Raising the Hazard Level ~7 Best Matches~: First ChapterThis unnamed test subject was given the Nebulasteam Gun after being transformed into Nebula Hell Bro's, an incomplete form of the Kaiser system

After being defeated and his transformation cancelled, Sento took him to safety, leaving the Nebulasteam Gun on the ground. Nariaki Utsumi recovered it and used the data to complete the Kaiser System.

Fu Washio
Remocon Bro's/Hell Bro's
The Phantom of the West (presumably) Shared with his brother as his transformation device and personal weapon in both Remocon Bro's and Hell Bro's forms
Rai Washio
Engine Bro's
The Phantom of the West (presumably) Shared with his brother as his transformation device and personal weapon.
Gentoku Himuro
Kamen Rider Rogue
ROGUE After becoming a Kamen Rider of Seito/Namba Heavy Industries Ltd., Gentoku uses a Nebulasteam Gun as his personal weapon after his Transteam Gun was taken.
Clone Hell Bro's
Clone Hell Bro's
Kamen Rider Build: Raising the Hazard Level ~7 Best Matches~: Final Chapter A Nebulasteam Gun was given to this clone of Hell Bro's so Utsumi could collect data on its fight with Build.
Evolto/Ryuga Banjo Kamen Rider Evol Tower of Destruction Borrowed briefly from Gentoku Himuro to use it against him and Kazumi Sawatari.
Kazumi Sawatari Kamen Rider Grease The Unstoppable Genius Borrowed briefly from Gentoku to allow him, Ryuga Banjo, and Takumi Katsuragi to escape from Evolto and MadRogue.



The Fullbottle-like Gears are loaded into the Nebulasteam Gun and the trigger is pulled to transform into a Kaiser(similar to loading a magazine). To transform into the Hell Bro's, the Gear Engine or Gear Remocon is inserted before being removed to insert the other and pull the trigger. The transformation commands for Mogami's Kaiser System are "Kaiser" (カイザー Kaizā) and "Bikaiser" (バイカイザー Baikaizā). The transformation command for Utsumi's Kaiser System is "Jundou" (潤動 lit. Lubricate).


The Nebulasteam Gun has 4 finishers: Funky Drive (ファンキードライブ Fankī Doraibu) with any Gear as a Kaiser, Funky Finish (ファンキーフィニッシュ Fankī Finisshu) with any Gear as Hell Bro's, Funky Break (ファンキーブレイク Fankī Bureiku) with the Crocodile Crack Fullbottle and Funky Attack (ファンキーアタック Fankī Atakku) with any other Fullbottle.

While in Rifle Mode, its finisher is the Funky Shot (ファンキーショット Fankī Shotto) the any Gear or the Crocodile Fullbottle and the Steam Attack with any other Fullbottle..

Kaiser Reverse fires a large energy shot at the enemy, then follows it up with a roundhouse kick that leaves behind a trail of red energy.

Kaiser fires a large blue energy gear at the enemy.

Remocon Bro's shoots an turquoise energy gear at the enemy. This finisher can be accompanied with Engine Bro's using the Steam Blade to create a energy slash.

    • Clone Hell Bro's: He uses a stronger version of Remocon Bro's version attack that shoots two energy gears.

  • Crocodile Crack: Rogue fires a Cruncher Fang projection towards his target.

  • Phoenix: Rogue transforms into a mass of fire that resembles an energy phoenix which gives him temporary flight abilities. He can also carry other people.

  • Cobra: Hell Bro's shoots an energy cobra projection followed by three energy projections of gears. The cobra first attacks the enemy by itself before it and all of the gears attack together in quick succession.

  • Gear Engine: Engine Bro's shoots an energy-like engine bolt at the enemy.
    • Elek Steam: Remocon Bro's shoots an electric energy-like engine bolt at the enemy.

  • Crocodile Crack: Rogue fires a Cruncher Fang projection towards his target.

  • Bat: Remocon Bro's shoots a purple bat energy blast that detonates upon impact.

  • Phoenix: Rogue fires a flame blast towards his target.

  • Evoltic Attack (エボルテックアタック Eborutekku Atakku):
    • 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.

Behind the Scenes


The Nebulasteam Gun is voiced by KORBY, who also voiced the Build Driver.


  • The Kuroko (駆鱗) is the middle expression that 駆(Ku) + 鱗(Uroko) and Croco(dile) meet.
  • Both of Nebulasteam Gun and its weaker version has their toy version smaller (which is possibly due to safety reason). Interestingly, Transteam Gun has both small and big models used in the series (as Soichi Isurugi used the small one to transform and the big one once completing the transformation into Blood Stalk ).
  • While still used to transform into a Rider-like form, the design aesthetics draw parallels with the Lupin Gunner from Kamen Rider Drive.
    • Coincidentally, the users of the Nebulasteam Gun draw parallels from the user of the Break Gunner either appearing as mechanical like the Kaisers, or as a Rider, but using it as a sidearm, like Kamen Rider Rogue.
  • Nebulasteam Gun will announce "Lost Match" upon utilizing certain Fullbottles, this is likely to depict that these Fullbottles have no Best Matches for them.
    • These Fullbottles are later revealed to be connected to the Lost Fullbottles under Evolto's possession.
      • The Bat Lost Fullbottle is the only exception as it will announce "Fullbottle" instead due to sharing its Pin with its best match counterpart, which is used in the series by Kamen Rider MadRogue.
  • Due to sharing its Pin with the Engine Fullbottle, this one will be read as the "Gear Engine" if inserted on the DX Nebulasteam Gun.
    • If a Remocon Fullbottle is released, probably would be the same case.
  • The Gears' abioitc motifs (Engine and Remocon) do Best Match with the two biotic motifs used by Gentoku Himuro (Bat and Crocodile).


See Also


  1. Uchusen (宇宙船 Uchūsen) 159, page 39
Sento Kiryu (Takumi Katsuragi) - Ryuga Banjo - Kazumi Sawatari - Gentoku Himuro - Evolto - Nariaki Utsumi - Shinobu Katsuragi
Movie-exclusive: Kengo Ino - Killbus - Keiji Uraga
Transformation Gear
Fullbottles - Build Driver - Transteam Gun - (Great) Cross-Z Dragon - Sclashjellies - Sclash Driver - Hazard Trigger - Nebulasteam Gun - Cross-Z Magma Knuckle - Evol-Driver - 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
Touto: Needle Smash - Strong Smash - Burn Smash - Flying Smash - Mirage Smash - Square Smash - Press Smash - Ice Smash - Stretch Smash
Hokuto: Castle Hard Smash - Stag Hard Smash - Owl Hard Smash
Kaiser: Kaisei Mogami (World of Ex-Aid)
Kengo Ino - Ryoka Saiga - Mitsuomi Gobara - Evolto - Killbus
Keiji Uraga - Simon Marcus (Phantom Crusher)
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