Sarina Sonoda

Sarina Sonoda (園田 紗里奈, Sonoda Sarina) is a classical literature teacher at Amanogawa High School who is also Gentaro Kisaragi, Kengo Utahoshi, and Yuki Jojima's homeroom teacher. It is later revealed that she is the human identity of the Scorpion Zodiarts, a Horoscope who distributes Zodiarts Switches among the students.

Personality
Sonoda has a kind and gentle demeanor which made her popular with the students of AGHS. She believes in a friendly approach to the students in contrast to Chuta Ohsugi. As a part of Mitsuaki Gamo's inner circle, her task is to encourage individuality among students. However this pleasant personality is just a farce, that lays the groundwork for the Scorpion Zodiarts in its distribution of Zodiarts Switches.

As the Scorpion Zodiarts, Sonoda reveals her more brutal and manipulative nature. She uses the switchers' desire for personal vengeance against another student or the school to become Zodiarts. By knowing the student, she can determine which of them have the potential to make their Zodiarts form evolve and become more powerful. The Scorpion Zodiarts is not above using a former Zodiarts to become a Zodiarts again despite their protests, even to the extant of taking them by force. Among the Horoscopes, Sonada is the most loyal to Gamo and his cause; effectively being his right hand.

History
Prior to the start of the series, Ms. Sonoda was once a AGHS student until she met Kouhei Hayami and became the Canis Minor Zodiarts through a Zodiarts Switch he gave her. After several uses, the Switch entered its Last One State. In order to fully evolve, Sonoda threw away her humanity and her Switch and Zodiarts form evolved into the Scorpion Zodiarts.

From there, now a member of the Horoscopes, Ms. Sonoda became a teacher as she proceeds to find ideal students that would have the potential to become the remaining eight members. She first introduced Gentaro to the class on his first day, expressing her dismay of both him and Kengo leaving class as she would occasionally speak with Mr. Ohsugi about them and the eventual members of Kamen Rider Club. Ms. Sonoda would later assume her Zodiarts form to fight off Kamen Rider Fourze to keep him from meddling Chameleon Zodiarts's revenge on Miu during the Queen Festival. After the Chameleon's defeat; Ms. Sonoda is told not to destroy Fourze by Gamou, believing he can facilitate the Zodiarts' evolution.

Since then, as the Scorpion Zodiarts, Ms. Sonoda oversaw Unicorn Zodiarts's progress before his defeat, aided Hound Zodiarts, and offered Tomoko a Zodiarts Switch while the Altar Zodiarts was enacting her revenge on the school. However, during the Pyxis incident when she attempted to keep the Kamen Rider from ruining the Pyxis Zodiarts's murderous plan, the Scorpion Zodiarts finds herself outmatched by Fourze's Fire States as she barely escaped by using her cape to absorb the attack.

Later, now allowed to kill Fourze without restraint, Ms. Sonoda is assigned the task to tempt Toshiya Miura back into using a Zodiarts Switch, knowing the powerful addiction the former Orion Zodiarts now had. But Fourze's inference forces her to fall back by creating Dustards that she sends to kidnap Miura the next day. But the Kamen Rider Club's intervention forces the Scorpion Zodiarts to inject her venom into Gentaro so she can fulfill her mission. However, Miura remembers what Gentaro told him about his life before becoming a Zodiarts and rejects the Zodiarts Switch and Gentaro came back to help after being cured from the poison thanks to Kengo and the Medical Switch. Enraged, the Scorpion Zodiarts uses the power she recently received from Gamo to become Scorpion Nova. Fourze manages to get the monster into outer space and defeats her with the Rider Rocket Drill Great Space Kick sending her crashing back down into Earth uncermoniously. Left unconscious after impact, Ms. Sonada is spirited away by Hayami while he uses his Libra Zodiarts form's powers to cloak her in Gentaro's form to keep her identity a secret.

Relieved of the Scorpion Switch for her failure, Ms. Sonoda is forced to watch from the sidelines as Hayami educates her on their mission during the Perseus Incident. But with the sudden appearance of Kamen Rider Meteor during the Lynx incident, Ms. Sonoda manages to convince Gamou to give her a second chance and fights alongside Hayami in their Zodiarts forms against Fourze after he destroyed the Lynx Zodiarts. They managed to pressure the lone Rider until Meteor arrived and easily defeated her. Forced back into her human form, the Libra Zodiarts did not bother to mask her identity (though at least her face was obstructed) as he spirits her back to Gamou's lair where she learns that she of no more use to him and will be exiled into the Dark Nebula. Begging for another chance, Ms. Sonoda is horrified when the Virgo Zodiarts arrives to carry out the deed. Sucked into the vortex conjured by the Virgo Zodiarts, only Ms. Sonoda's Scorpion Switch remains on Earth.

Abilities
When her Canis Minor Zodiarts Switch entered it's Last One State, Sonada threw away her humanity and evolved into the Scorpion Zodiarts which also increased her age. Through the red Scorpion Switch, Ms. Sonoda becomes the powerful Scorpion Zodiarts based on the Scorpius constellation. Her fighting style involves kicking, the powerful clawed gauntlets, and the stinger on the back of her head which can extend to various distances to be used as a whip, and has the compacity to inject powerful toxins based on Cosmic Energy. The Scorpion Zodiarts has demonstrated the ability to summon Dustards It's final ability is to transform into a more powerful scorpion-man-like form called Scorpion Nova (スコーピオン・ノヴァ, Sukōpion Nova), which not only makes her stronger but also makes her body a time bomb that could wipe out an entire city.

Trivia

 * Her being the former Canis Minor Zodiarts is the reason why Hayami calls her "pup".
 * Prior to being officially revealed, the audience could find out Ms. Sonada's secret identity by rearranging her name into the anagram Sasori na no da (さそりなのだ), which means "I am the scorpion".
 * Sonoda is the first Horoscope that Kamen Rider Fourze defeated. She is also the one who gave him the hardest time in battle before the Rider obtained Fire States.
 * Sonoda's preference of Switch distribution is towards students looking for vengence is akin to how Gaea/Apollo (depending on the version of the myth) sent the Scorpion after being offended by Orion. The first non-Horoscope Zodiarts is the Orion.
 * Also, the Orion Switcher was the one who lead to Sonoda's downfall, which is ironic, given the mythologies in the constellations.