Nebulasteam Gun

The Shock Scale Smoke Pistol Nebulasteam Gun (撃鱗煙銃ネビュラスチームガン) 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). Takumi Katsuragi who at the time was his assistant, would later create a simplified and weaker version of the device called the Transteam Gun. Nariaki Utsumi would eventually update the Kaiser system for the use of Namba Heavy Industries Ltd.

The Nebulasteam gun is the personal weapon of Kamen Rider Rogue, and the transformation device of the Kaisers. It combines with the Steam Blade to form the Nebulasteam Rifle (ネビュラスチームライフル).

Transformation
The Fullbottle-like Gears are loaded into the Nebulasteam Gun and the trigger is pulled to transform into a Kaiser. 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) and "Bi-Kaiser" (バイカイザー). The transformation command of Utsumi's Kaiser System is "Jundou" (潤動).

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

While in Rifle Mode, its shooting finisher is Funky Shot (ファンキーショット) with any Fullbottle or Gear.

Funky Drive=
 * Gear Engine: Kaiser Reverse fires a massive energy shot at the enemy, then follows it up with a roundhouse kick that leaves behind a trail of red energy.
 * Gear Remocon: Remocon Bro's shoots an energy gear at the enemy. This finisher can be accompanied with Engine Bro's energy using the Steam Blade to create a energy slash. Clone Hell Bro's uses a stronger version of this attack that shoots two energy gears.

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