|This article is about a/an rider in Kamen Rider Gaim.|
Masako Suzuka (鈴鹿 まさこ Suzuka Masako) is the main antagonist of Gaim Gaiden: Kamen Rider Gridon VS Kamen Rider Bravo. She is the secretary of Hideyasu Jonouchi who uses the Helheim Lockseed to transform into Kamen Rider Sylphi (仮面ライダーシルフィー Kamen Raidā Shirufī).
Posing as a normal secretary, she is revealed as the mastermind behind the creation of mutated Helheim fruits, and presumably as the one who transformed Oren into the berserk King Durian Arms form (as the twin vines appearing from a Helheim crack that transformed Oren's Lockseed earlier did so in an identical manner to the ones involved in Masako's transformation).
- "This won't end here...Your battle will never end."
- ―Sylphi's last word before she vanished[src]
When Takatora revealed that he had arranged the battle between Jonouchi and Oren in order to draw the real culprit out and confronted her, she admitted her scheme and transformed into Kamen Rider Sylphi. Takatora battled her while Jonouchi struggled to help Oren regain his control over his mind. After she was defeated by Zangetsu Kachidoki Arms, she told him that his battle would never be over. As she vanished, he simply said that that was as it should be.
To be added
Like with the other Armored Riders, Kamen Rider Sylphi's forms are called Arms (アームズ Āmuzu). Her Sengoku Driver plays Japanese horagai music and announces "Soiya" (ソイヤ) before every transformation.
By pressing the Sengoku Driver's Cutting Blade down on the Lockseed after transforming from one to three times, Sylphi can activate one of three finishing moves based on her current Arms form: Squash (スカッシュ Sukasshu), Au Lait (オーレ Ōre), or Sparking (スパーキング Supākingu).
The Ride Wear (ライドウェア Raido Uēa) is Sylphi's default form undersuit which is briefly seen during Sylphi's transformation sequence, before the Armor Part attaches or when she changes Arms. Unique to her is that the Helheim Forest's plants materializes around her and forms the suit, unlike the usual Armor Part descending from a Crack and attaching onto the head of the user. Although there is no Ride Wear for her, she still has her own Rider Indicator.
- "Soiya! Hell's Arms! Shinryaku no kajitsu!"
- ―Transformation announcement[src]
Hells Arms (ヘルズアームズ Heruzu Āmuzu) is Sylphi's Helheim's Fruits-based default form that is accessed through the Helheim Lockseed.
While assuming Hells Arms, Sylphi dons the Hells Armor Part (ヘルズアーマーパート Heruzu Āmā Pāto) and the Arms Weapon Hells Cane.
This form's finisher is an unnamed Rider Thrust: Sylphi activates the Sparking function on her Sengoku Driver, then jumps and charges with her weapon, forming a purple energy on the tip to stab the opponent with.
Appearances: Gaim Gaiden: Kamen Rider Gridon VS Kamen Rider Bravo
- Sylphi's suit is retooled from Kamen Rider Idunn, which in turn was retooled from Kamen Rider Jam, which itself was a retool of Kamen Rider Kamuro.
- Sylphi currently has the distinction of being the last female Heisei-era Rider to appear during the Reiwa-era, which was previously held by Tsukuyomi who had her debut transformation in an episode that aired after the new era transition, predating the first official Reiwa-era Rider, Yua Yaiba.
- Masako's actress, Tomomi Jiena Sumi is a member of the Kamen Rider Girls and represented Gaim until 2016. Jiena is the first and only Kamen Rider Girls member to portray an actual Kamen Rider.
- Her pole-arm weapon is recolored and modified from Kamen Rider Kurokage’s Kagematsu.