|This article is about a/an weapon in Kamen Rider Build.|
The Valve Rotator Steam Blade (バルブ回転スチームブレード Barubu Kaiten Suchīmu Burēdo) is a weapon wielded by users of the Transteam Gun or the Nebulasteam Gun. It combines with the Transteam Gun to form the Steam Rifle (スチームライフル Suchīmu Raifuru) or the Nebulasteam Gun to form the Nebulasteam Rifle (ネビュラスチームライフル Nebyura Suchīmu Raifuru).
The Steam Blade splits at the handle and its blade connects to the front of the Transteam Gun/Nebulasteam Gun, while the handle connects to the back of the Gun to form the Steam Rifle.
The Steam Blade's valve turns in both Blade Mode and Rifle Mode to change attack types.
- Elek Steam (エレキスチーム Ereki Suchīmu): Night Rogue or Blood Stalk shoot electricity at the enemy.
- Ice Steam (アイススチーム Aisu Suchīmu): Night Rogue or Blood Stalk perform a series of ice slashes at the enemy causing them to freeze.
- Devil Steam (デビルスチーム Debiru Suchīmu): Night Rogue or Blood Stalk use the Steam Blade to emit steam with a Nebula Gas-compound that can turn humans into Smash or make a Smash grow to gigantic proportions. In Rifle mode it fires a steam bullet which will home in on the target and directly injects them with Nebula Gas when it hits them.
The Steam Rifle has 2 shooting finishers: Steam Shot (スチームショット Suchīmu Shotto) with a Faust Fullbottle and Steam Attack (スチームアタック Suchīmu Atakku) with a normal Fullbottle.
The Nebulasteam Rifle's finisher is the Funky Shot (ファンキーショット Fankī Shotto) with a Fullbottle or a Gear.
- Bat: Night Rogue shoots a powerful steam blast at the enemy.
- Cobra: Blood Stalk shoot a purple cobra energy blast that detonates upon impact.
- Rocket: Blood Stalk shoots a powerful blast attack that takes the form of a rocket. The rocket flies around the enemy before coming to the ground for an explosion.
- 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.
- Gear Remocon:
- 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.
- The Steam Rifle's design resembles the real-life Mk 14 Enhanced Battle Rifle, otherwise known as the M14 EBR.