Kazumi Sawatari

Kazumi Sawatari (猿渡 一海) is Kamen Rider Grease (仮面ライダーグリス), who hails from Hokuto and is the leader of the Hokuto Three Crows.

Character History
Little is known about Kazumi's past: like Sento Kiryu, Kazumi is an amnesiac, although he seems unconcerned about his past.

Shortly before Hokuto invaded Touto for the Pandora Box, Kazumi was chosen to lead a strike team in charge of retrieving Touto's FullBottles and Pandora Box panels. He was given a Sclash Driver by Soichi Isurugi, allowing to become Kamen Rider Grease. He also somehow save the families from a three young men, which would later become his underlings known as Hokuto Three Crows, although Kazumi himself claims that he didn't do anything to them.

Hokuto-Touto War
Kamen Rider Grease stole the Phoenix and Robot Fullbottles from Sento.

As Kamen Rider Grease, Kazumi led the Hokuto advance into Touto once war was declared by Prime Minister Yoshiko Tajimi. Penetrating the Skywall, Grease destroyed many Touto Guardians.

Ryuga Banjou encountered him as he searched for the Hokuto Three Crows. A Strong Smash Hazard appeared and began attacking bystanders, and as Ryuga put on the Build Driver, Kazumi destroyed the Smash in one punch using his hidden Helicopter Fullbottle before leaving. Later, after Ryuga and Sento had defeated the Hokuto Three Crows in Ryuga's first fight as Cross-Z Charge, Kazumi showed up to challenge them with his own Sclash Driver.

Personality
Kazumi's demeanor alternates between calm and composed to maniacal and ruthless, depending on whether he's fighting or not. Presumably due to his usage of the Sclash Driver, Kazumi is obsessed with battle and finding a worthy opponent. He is not afraid to use lethal methods, going as far to even try to deliver a Rider Kick at an untransformed Banjou.

However, Kazumi operates by a certain code: he insists on not targeting civilians as long as they stay out of the way, and decided against taking Build's FullBottles due to him butting in the battle, much to the trio and Hokuto Prime Minister dismay. Kazumi is an avid fan of Mii-tan, allowing Sento and Banjou to escape and cancelled Akaba's attack, since Misora is the one who helped them.

Powers and Abilities

 * Fullbottle Augmentation: By using a Fullbottle in his hand without transforming, Kazumi can gain abilities based on said Fullbottle's traits:
 * Helicopter: Allows Kazumi to perform fiery punches. First used to defeat a Strong Smash Hazard.

Weaknesses

 * Mii-Tan: Since Kazumi is a huge fan of Mii-tan, he quickly loses his fighting will and even allows his enemy to escape if Misora is the one who helped them. It's hinted that he might have a crush on Mii-tan.

Forms
Grease "Tsubureru! Nagareru! Afurederu! Robot In Grease! Buraa!"

- Transformation announcement

Rider Statistics Ability Perimeters: Grease's base form is accessed by inserting the Robot Sclashjelly into the Sclash Driver and pumping the lever.
 * Rider Height: 203.0 cm
 * Rider Weight: 118.3 kg
 * Punching Power: 31.3 tons
 * Kicking Power: 34.3 tons
 * Maximum Jump Height: 54.0 m
 * Maximum Running Speed: 100 m. per 2.5 sec.

Unlike Cross-Z Charge who has more punching power, Grease has more kicking power. Besides that, Grease shares similar stats with Cross-Z charge in terms of jumping power and speed.

Also, as he is presumably much more experienced with the Sclash Driver, he is able to fight against and defeat Cross-Z Charge at ease, even when the latter has similar power stats as him.

Grease's personal weapon is the Twin Breaker.

Grease has two different finishers:
 * Sclash Driver finisher:
 * Scrap Finish (スクラップフィニッシュ):
 * Rider Kick (ライダーキック): Grease uses his Machine Pack Shoulder (マシンパックショルダー) to generate black grease-like energy like a rocket in order to propel himself forward as he delivers a Rider Kick to the enemy, coated in gold energy.
 * Rider Punch (ライダーパンチ):
 * Discharge Crash (ディスチャージクラッシュ):
 * Helicopter Fullbottle: Grease creates a helicopter blade in his right arm, gaining the ability to fly.
 * Twin Breaker finishers:
 * Beam Mode:
 * Single Finish (シングルフィニッシュ): Grease channels the energy of a Fullbottle or the Robot Sclashjelly and performs a powerful blast.
 * Fullbottle:
 * Sclashjelly:
 * Robot Sclashjelly: Grease shoots the enemy with gold lightnings in rapid succession.
 * Twin Finish (ツインフィニッシュ): Grease channels the energy of 2 Fullbottles or a Fullbottle and the Robot Sclashjelly and performs a powerful blast.
 * 2 Fullbottles:
 * Fullbottle + Sclashjelly:
 * Helicopter Fullbottle + Robot Sclashjelly: Grease shoots the enemy with projections of gold helicopter blades.
 * Attack Mode:
 * Single Break (シングルブレーク): Grease channels the energy of a Fullbottle or the Robot Sclashjelly and performs a powerful slash.
 * Fullbottle:
 * Sclashjelly:
 * Twin Break (ツインブレイク): Grease channels the energy of 2 Fullbottles or a Fullbottle and the Robot Sclashjelly and performs a powerful slash.
 * 2 Fullbottles:
 * Fullbottle + Sclashjelly:

Appearances: Build Episodes 16, 18, 19, Kamen Rider Build: Birth! KumaTelevi!! VS Kamen Rider Grease!

Devices

 * Sclash Driver - Transformation device.
 * Sclashjellies - Transformation trinkets.
 * Helicopter Fullbottle

Weapons

 * Twin Breaker

Portrayal
Kazumi Sawatari is portrayed by Kouhei Takeda (武田 航平), who is more previously well known for his portrayal of Otoya Kurenai in Kamen Rider Kiva. As Kamen Rider Grease, his suit actor is Satoshi Fujita (藤田 慧).

Etymology
Following Sento and Ryuga, one of the kanji used to spell his name also represents an animal, Sa (猿), which poetically means "monkey". It can be refer to grease monkey, an English slang term for the mechanics.