Zodiarts

The Zodiarts (ゾディアーツ, Zodiātsu) are the antagonists in the Kamen Rider Fourze. Each of the Zodiarts is themed after one of the 88 Western constellations, and each Zodiarts body is decorated with the pattern of the constellation it is named after. The name "Zodiarts" is derived from the English word "zodiac".

A Zodiarts is a monstrous construct that is produced when a Zodiarts Switch (ゾディアーツスイッチ, Zodiātsu Suitchi) is activated by a person, then on known as a Switcher (スイッチャー, Suitchā). From there, a Zodiarts Switch gathers a mysterious energy from space called Cosmic Energy (コズミックエナジー, Kozumikku Enajī) around a human, turning them into a Zodiarts.

After the Zodiarts Switch is used several times in a row, it will announce "Last One" and the Zodiarts Switch will change its appearance, growing spikes and an eyeball-like structure, as well as changing the position of the button. When the Switcher activates the Switch at this point, the transformation becomes irreversible as the Switch drains its Switcher of their conscious mind and uses it to become a Zodiarts permanently. The Switcher's empty body is ejected from the Zodiarts, covered in a cobweb-like substance. In this state, a Zodiarts becomes extremely powerful to the point that its destruction would cause a massive explosion that would destroy everything surrounding it. A Zodiarts, especially one at its strongest, can only be defeated if targeted at point of its body where the Zodiarts Switch is located. From there, Kamen Rider Fourze can use one of his Limit Break (リミットブレイク, Rimitto Bureiku) finishing attacks to destroy the monster and get the Zodiarts Switch.

However, if a Zodiarts should go beyond "Last One", they will evolve into a Horoscopes member, which are modeled after the 12 constellations of Western astrology.

Once properly switched off, the Zodiarts Switch will vanish into a singularity, keeping its user from ever becoming that particular Zodiarts again. However, it is still possible for a Switcher to become a Zodiarts again through another Zodiarts Switch. It also appears that a Switcher gains an addiction to Cosmic Energy after using a Switch, which only helps in making them Zodiarts again.

Zodiarts are collectively named after the "Zodiac".

Orion
Toshiya Miura (三浦 俊也, Miura Toshiya) is a member of the AGHS football club who became tired of how the team's members, particularly captain Shun Daimonji, treat him as their slave and never let him have a chance on the field. To get back at Shun, he is given a Zodiarts Switch that allows him to become the Orion Zodiarts (オリオン・ゾディアーツ, Orion Zodiātsu), a Zodiarts with intense brute strength. Although he is initially defeated by the first appearance of Kamen Rider Fourze by the Kamen Rider's Rocket Drill Kick, the mysterious Scorpion Zodiarts returns the Zodiarts Switch to Miura, allowing him to use it once more to confront Shun. After Tomoko Nozama reveals the identity of the Zodiarts to Gentaro Kisaragi and Yuki Jojima, they reach Miura in time to convince him not to go through with his plans. However, Shun pushes Miura over the edge by kicking him out of the football club, driving him to use the Zodiarts Switch just as it enters its Last One state, also arming his Zodiarts form with the Lemnos Club (レムノスクラブ, Remunosu Kurabu) and the Chios Shield (キオスシールド, Kiosu Shīrudo), though he loses both weapons during the ensuring fight. As the monster has amassed enough energy to blow up the stadium, Kengo Utahoshi directs Kamen Rider Fourze to take the Orion Zodiarts into the upper atmosphere in order to destroy him with the Rocket Drill Space Kick, allowing the Zodiarts Switch to be turned off (after re-entering the atmosphere).
 * Switcher: Toshiya MiuraOrion.jpg
 * Episodes: 1-2
 * Defeated by: Kamen Rider Fourze Base States' Rocket Drill Kick (Ep. 1), Rocket Drill Space Kick (Ep. 2)
 * Constellation Base: Orion

Chameleon
Tamae Sakuma (佐久間 珠恵, Sakuma Tamae) is a third-year student who is in the cheerleading squad, in addition to being one of Miu Kazashiro's "sidekicks". However, Tamae has become tired of Miu's two-year winning streak in the annual Queen Festival, a contest that votes for the "queen" of the student body. To stop Miu from winning her third year so she would be able to win the contest herself, Tamae is given the Zodiarts Switch that allows her to become the Chameleon Zodiarts (カメレオン・ゾディアーツ, Kamereon Zodiātsu), a Zodiarts that can appear invisible as well as attack with its powerful tongue-like tendrils. To orchestrate her plan to remove Miu from the contest, Tamae begins to attack students that could be potential threats to her success. Then, when Miu takes the stage for the talent competition, Tamae fakes being attacked herself so she would be able to transform and cause a commotion, allowing for a video of Miu lambasting the student body to play. When her identity is revealed, Tamae fakes remorse to catch Miu off guard and injures her severely to remove her from the contest. However, Miu musters up enough strength to return to school despite her yet-to-recover injuries and wins back the hearts of the student body with her powerful speech. Tamae, enraged that her plan has failed, ignores Kengo's warning against using her Zodiarts Switch when it enters its Last One state. She attacks Miu as the Chameleon Zodiarts once more, but Kamen Rider Fourze is able to save the school's reigning "queen" and eventually destroys the Zodiarts with his Rider Rocket Drill Kick, gaining access to the Zodiarts Switch to shut it off. After Miu wins the contest for the third year in a row, she forgives Tamae for her actions, and renews their friendship under the promise that Tamae would beat Miu through honest means.
 * Switcher: Tamae SakumaFourze112.jpg
 * Episodes: 3-4
 * Defeated by: Kamen Rider Fourze Base States' Rider Rocket Drill Kick
 * Constellation Base: Chamaeleon

Unicorn

 * Switcher: Fumihiro NittaUnicorn.jpg
 * Episodes: 5-6
 * Defeated by: Kamen Rider Fourze Elek States' Rider Ten Billion Volt Break
 * Constellation Base: Monoceros

Fumihiro Nitta (新田 文博, Nitta Fumihiro) is a first-year student member of the fencing team who has a grudge against JK for being used by him to be his human shield from bullies. The Scorpion Zodiarts gives him a Zodiarts Switch that allows him to transform into the Unicorn Zodiarts (ユニコーン・ゾディアーツ, Yunikōn Zodiātsu). He is able to convert his horse-faced mask into the Longsword Monarch (長剣 モナーク, Chōken Monāku) rapier, and becomes a force to reckon with in a fight thanks to Nitta's already impressive fencing skills, though his non-weaponry fighting skills are frankly deplorable. After capturing JK, Nitta amusingly allows him to contact someone for help, with full knowledge that no one in his circle would save him, after scaring off much of them. However, Gentaro proves Nitta wrong as he manages to become Kamen Rider Fourze and assume Elek States for the first time and destroys the Zodiarts with the Rider Ten Billion Volt Break. Though JK intends to beat the daylights out of Nitta for the latter's boorish actions, Gentaro tells him not to.

Hound
Teruhiko Satake (佐竹 輝彦, Satake Teruhiko) is the rebellious son of AGHS's Takashi Satake. Though he is a student who scores good grades, he is unhappy with his life and adopts delinquent hobbies and mannerisms. At some point, he receives a Zodiarts Switch from the Scorpion Zodiarts in order to transform into the Hound Zodiarts (ハウンド・ゾディアーツ, Haundo Zodiātsu) and uses his newly gained abilities to be himself and go on a rampage, or "hunting" as he calls it, attacking anyone nearby. He fights with his powerful claws and the chain that hangs around his neck. The Hound Zodiarts can also fire a barrage of needle-like energy bullets from the dog's face on his chest. Eventually in his Last One state, the Hound Zodiarts gains a thickened hide and none of the usual attacks from the Kamen Rider work on him. While the Scorpion Zodiarts supports the Hound Zodiarts in fighting Kamen Rider Fourze in Elek States, Shun Daimonji arrived in a big flair, he piloting the Powerdizer to hold the Scorpion off so the Kamen Rider can fight the Hound Zodiarts one-on-one. The Hound sent Fourze flying, though Shun snagged Fourze and sent him right back at the Hound, allowing Fourze to destroy him with the Rider Lightning Drill Kick.
 * Switcher: Teruhiko SakateHound.jpg
 * Episodes: 7-8
 * Defeated by: Kamen Rider Fourze Elek States' Rider Lightning Drill Kick
 * Constellation Base: Canes Venatici

Altar
Ritsuko Usaka (鵜坂 律子, Usaka Ritsuko) is a girl who has been blamed for various unexplained things in Amanogawa High, giving into the persecution and becoming the bad girl as she forms her own witches' coven called the Lunar Witches (月世界の魔女, Gessekai no Majo) with other scorned social outcasts. She is given a Zodiarts Switch that allows her to transform into the Altar Zodiarts (アルター・ゾディアーツ, Arutā Zodiātsu), granting her poweful telekinetic powers via her special Aradia Staff (アラディアスタッフ, Aradia Sutaffu). Ritsuko's passion for the occult evolved her Zodiarts form to also use pyrokinetic powers. Creating moon pendants for her followers to wear, Ritsuko uses these to channer her powers to make it appear that she and the members of her group are actually witches until Kengo exposes the deception. Later, after using the Zodiarts Switch in its Last One state, the Aradia Staff was destroyed by Shun in the Power Dizer in a diving save before she could execute her scheme of burning down the school. Enraged at the act of defiance, the Altar Zodiarts overpowers Kamen Rider Fourze in Elek States until he assumes Fire States and absorbs her fire-based attacks before destroying her with the Rider Exploding Shoot.
 * Switcher: Ritsuko UsakaAltar.jpg
 * Episodes: 9-10
 * Defeated by: Kamen Rider Fourze Fire States' Rider Exploding Shoot
 * Constellation Base: Ara

Pyxis
Hiroki Makise (牧瀬 弘樹, Makise Hiroki) is the president of Amanogawa High School's astronomy club who has an obsession with Yuki Jojima and stalks her. He grew jealous of her spending time with Gentaro and the Kamen Rider Club instead with him and his club. Hiroki gained a Zodiarts Switch that allows him to become the stag beetle-like Pyxis Zodiarts (ピクシス・ゾディアーツ, Pikushisu Zodiātsu), which can use its dowsing rod-like horns on his arms to track down whatever the user wishes, as well as to change the motion of whatever object he points them at. In combat, the Pyxis Zodiarts can use his arm blades to slash his opponent, but as Makise is not a competent fighter, he is not very good with them. After seeing her with Gentaro, overpowered by Kamen Rider Fourze and the Powerdizer in their first fight, Makise decides to make Yuki pay for her choice in friends, losing all infatuation with her in the process. To that end, he pretends to help Yuki find the missing locker that connects to the Rabbit Hatch so he can destroy it and make her cry.
 * Switcher: Hiroki Makise
 * Episodes: 11-12
 * Defeated by: Kamen Rider Fourze Elek States' Rider 10 Billion Volt Shoot
 * Constellation Base: Pyxis

Though Kamen Rider Fourze tries to stop him, the Pyxis Zodiarts takes advantage of the Kamen Rider Fourze's Launcher Module to redirect its missiles at the locker and destroy it. However, the locker was revealed to be not the same one, though Makise meanwhile decides to extract his revenge on every girl who rejected him by having them get on a bus which would drive over an unfinished bridge. However, assuming his Last One state, the Pyxis Zodiarts's scheme fails as Shun in the Powerdizer made a last-minute save, allowing Fourze to assume Elek States, then uses the new Stealth Module to disable the Zodiarts' abilities by breaking the scythe-like protusions on his arms with the help from Kengo before destroying the Zodiarts. Back in his body, Makise receives swift and brutal retaliation from the kidnapped girls.

Perseus
Soshi Matoyama (元山 惣帥, Matoyama Sōshi) is the president of the AGHS art club who wishes to create a perfect piece of art. He is approached by the Libra Zodiarts and is given a Zodiarts Switch that allows him to transform into the Perseus Zodiarts (ペルセウス・ゾディアーツ, Peruseusu Zodiātsu), arming him with the gigantic Oracle Sword (オラクルソード, Orakuru Sōdo). He also has the Head of Medusa (ヘッドノメドゥーサ Heddo no Medūsa) on his left hand, enabling him to turn anything he grabs with it to stone. Matoyama uses his power to attack and petrify anyone and anything that interferes in his work's creation. Thought his Last One form is destroyed by Kamen Rider Fourze Fire States, the Zodiarts Switch recreates the Perseus Zodiarts's body, as well as gaining the ability to fire petrification beams from his Medusa hand, making him far more dangerous than he was before before.
 * Switcher: Soshi Matoyama
 * Episodes: 15-16
 * Defeated by: Kamen Rider Fourze Fire States' Rider Exploding Shoot (15); Kamen Rider Fourze Base States' Rider Rocket Drill Kick (16)
 * Constellation Base: Perseus

However, as a result of Gentaro's attempts to reach him, the Perseus Zodiarts realizes he made a grave error in judgement over his hyper-critical actions after seeing how his earlier painting has inspired the kindergarteners to make their own works. The Perseus Zodiarts then accepts Gentaro's friendship with the intent of refusing to his body before the Libra Zodiarts converts him into a berserker for no longer having the potential to evolve. However, with the help of the newly-arriving Kamen Rider Meteor holding the Libra Zodiarts at bay, Kamen Rider Fourze uses the Pen Switch to disable the brainwashed Perseus Zodiarts before destroying him with the Rider Rocket Drill Kick. Back in his body, Matoyama is later seen creating a new painting of Mount Fuji to give to the kindergarteners as a means to start over.

Canis Minor
Sarina Sonada (園田 紗里奈, Sonoda Sarina) is the Scorpion Zodiarts of the Horoscopes, but she wasn't always that way. She started out as an ordinary student at AGHS until she met Hayami and was given a Zodiarts Switch that allowed her to become the Canis Minor Zodiarts (カニスミノル・ゾディアーツ Kanisu Minoru Zodiātsu), although it is unknown what this Zodiarts was capable of. As Fourze didn't existed back then, this allowed her to reach Last One unopposed, where she went through the Zodiarts' evolution and ascended into the Horoscopes' ranks as the Scorpion Zodiarts.
 * Switcher: Sarina Sonada
 * Episodes: 15
 * Constellation Base: Canis Minor

Lynx
Masao Nonomura (野々村 公夫, Nonomura Masao) is an AGHS student who is Kengo's rival. The Zodiarts Switch given to him by the Libra Zodiarts enables him to transform into the Lynx Zodiarts (リンクス・ゾディアーツ, Rinkusu Zodiātsu) who is agile and has sharp claws on both of his hands. Due to the infighting between Kamen Riders Fourze and Meteor, the Lynx Zodiarts is able to reach the stage of potential that will enable him to transform into one of the Horoscopes, which Kamen Rider Meteor believes will be the Aries Zodiarts.
 * Switcher: Masao Nonomura
 * Episodes: 17-18
 * Constellation Base: Lynx

Trivia

 * The Zodiarts are similar to the Dopants in how they are humans powered by dark versions of the main rider's power source. Unlike the Dopants, getting rid of a Zodiarts requires the Zodiarts Switch to be manually switched off instead of it being destroyed after defeat.
 * Most of the constellations that make up the Zodiarts' base are lesser-known.
 * Each of the Zodiarts have their powers or weapons themed after either their constellation or their own personalities and/or natural abilities. In example:
 * The Orion Zodiarts got armed with a club and shield in the Last One stage because the Orion constellation drawings often had him holding a club and a shield
 * The Chameleon Zodiarts' invisibility not only stems from the chameleon's extraordinary camouflage abilities, but the fact the Switcher blended in under Miu's nose the entire time.
 * The Unicorn Zodiarts has a rapier, due to him being in the Fencing Club.
 * The Hound Zodiarts had a spiked chain for a weapon to symbolize the Switcher's desire to break free of the "chain" his father had on him.
 * The Alter Zodiarts had psychokinesis and pyrokinesis to tie in the power of the occult and the Ara constellation's shape being shaped as a pyre.
 * The Pyxis Zodiarts has his dowsing and re-directing powers because the Pyxis constellation's shape is a mariner's compass.
 * As of now, there has been only two Zodiarts that appeared the following episode after they were defeated by a Limit Break: the Orion and Perceus Zodiarts, both of which have ties to Greek mythology.