Gentoku Himuro

Gentoku Himuro (氷室 幻徳) is one of the main villains in Kamen Rider Build. The head of the Touto Institute of Advanced Matter Physics, he is also the current acting Prime Minster of Touto, after taking over the role from his hospitalized father, Taizan Himuro. . Gentoku is also the leader of Faust, and the true idenity of Night Rogue (ナイトローグ), informally known to Build as simply the Bat Man (蝙蝠男). He is a mysterious masked figure that is present during Faust's experiments that turn victims into Smash, including the one from Sento Kiryu's memories.

Character History
Gentoku was in the audience of the return ceremony when the Skywall was raised. Within a decade of the disaster, he became an aide to the Prime Minister of Touto, overseeing research of Pandora Box. He later watches over the human experimentation it conducts and appears in Sento Kiryu's mostly forgotten memories from before his escape, sitting atop a throne. According to Gentoku himself, the reason behind these experimentations is to accomplish one of Faust's objectives: to create the "Ultimate Lifeform."

Gentoku was seen possessing the Rocket Fullbottle. Blood Stalk later uses this bottle with his Transteam Gun before it is stolen by Ryuuga and given to Sento.

Personality
Gentoku is a composed and generally calm man, rarely changing his tone of voice unless agitated. Underneath his cool exterior, he is a man with questionable morals at best: he flirted with a journalist, and referred to Ryuga and Kamen Rider Build as toys, as well as his fiery temper whenever he commands his soldiers. During a conversation with Gentoku, Blood Stalk reveals that Gentoku's goal is to mass produce Kamen Rider technology from his experiments for military use. To what reason or purpose is unclear, but Gentoku seems determined to see this project succeed and will do everything he can to silence or stop anyone who will interfere with this plan. He also didn't hesitate to kill his decoy with his own hand to get press in his favor.

It is likely that some of his negative personality traits are a result of his exposure to Pandora Box during the Skywall disaster. One of those traits seems to be episodes of paranoia and aggression, urging his father that they need a military to crush Seito and Hokuto before they crush Touto, believing they are out to get the capital and superior military might can stop their advance.

As Night Rogue, he is very malicious. Seeing innocent people as mere guinea pigs, he doesn't hesitate to experiment on them, even when fully knowing that his subjects would be too weak to survive. Despite his cold and calculating personality, Rogue has his own standards and shows little to no tolerance with insubordination. He is easily vexed each time Stalk goes against his orders, which drives a wedge between their collaboration.

Powers and Abilities

 * Wall Crawling: True to his animal motif, Night Rogue can stay unto ceiling structures.
 * Typhoportation: He can escape any situation by turning himself into a puff of smoke. These smoke first unleashed from his suit before covering his body.
 * Hazard Level 3+: According to Gentoku as Rogue, his Hazard Level is above 3 (stated to be much higher than Cross-Z's), thus making him capable of fighting on par with the Kamen Riders.

Forms
"Bat! Mistmatch! Bat...Ba-Bat... Fire!"

- Transformation announcement

Ability Perimeters: Like Blood Stalk, Night Rogue's form is accessed with the Transteam Gun and the Bat Fullbottle.
 * Height: 197.5 cm.
 * Weight: 103.0 kg.
 * 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.

Night Rogue seems to possess a degree of steam manipulation as he can turn himself into steam to quickly travel long distances or to summon his Steam Blade. Night Rouge is also shown to be able to fly as well as stand upside down by using his feet to somehow cling to ceilings like a real bat. He can also execute an electrified Rider Punch-esque attack where his fist glows blue with electric energy and hits the target.

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. He is also able to overpower Blood Stalk in one-on-one combat, despite having marginally lower stats.

With the Steam Blade or the Steam Rifle, he can use the following attacks:
 * Elek Steam (エレキスチーム): Night Rogue shoots electricity at the enemy.
 * Ice Steam (アイススチーム): Night Rogue performs a series of icy slashes at the enemy causing them to freeze.
 * Devil Steam (デビルスチーム): Night Rogue fires a "steam" bullet which will home in on the target and inject them with an unknown compound when it hits them. When used on a human, the person will turn into a Smash. When used on a Smash, the Smash will grow to gigantic proportions.

Night Rogue has 4 finishers:
 * Transtream Gun finishers:
 * Steam Break (スチームブレイク): Night Rouge channels the powers of a Faust Fullbottle and performs a powerful blast attack.
 * Bat:
 * Steam Attack (スチームアタック): Night Rouge channels the powers of a normal Fullbottle and performs a powerful blast attack.
 * Steam Rifle finishers:
 * Steam Shot (スチームショット): Night Rouge channels the powers of a Faust Fullbottle and performs a powerful steam blast attack.
 * Bat:
 * Steam Attack (スチームアタック): Night Rouge channels the powers of a normal Fullbottle and performs a powerful steam blast attack.

Appearances: Build Episodes 1-7, Transformation Lessons (Night Rogue), Build 8-11

Devices

 * Transteam Gun - Transformation device and personal weapon.
 * Fullbottles - Transformation trinkets.

Weapons

 * Steam Blade - Standard sidearm weapon. Can combine with the Transteam Gun to form the Steam Rifle.

Portrayal
Gentoku is portrayed by Kensei Mikami (水上 剣星). As Night Rogue, his suit actor is Jun Watanabe (渡辺淳), who played Secondary Riders since Kamen Rider Drive.

Etymology
Night Rogue's name is a loose play on English words "Nitro" and "Rogue".