Gentaro Kisaragi

Kamen Rider Fourze (仮面ライダーフォーゼ, Kamen Raidā Fōze) is the main protagonist in the series of Kamen Rider Fourze. His name roughly says Forty, as well as a combination of "Four" and "Zero", an indication of the Kamen Rider Series' 40th Anniversary and the forty different powers and weapons he can access with the Astroswitches.

Gentaro Kisaragi
Gentaro Kisaragi (如月 弦太朗, Kisaragi Gentarō) is a second year student in Amanogawa High School, who has a delinquent Yankee-like appearance wearing a short jacket over a T-shirt and baggy pants, with his hair in a pompadour, rather than the clean cut uniform worn by other AGHS students; but is actually really friendly and wants to make friends with people in the school. He is willing to go the extra mile and do bizarre things to get to know someone he wants to befriend better. He puts friendship above anything else and values every friend that he has, to the point of crying hard whenever he hears a sad story of someone he considers a friend. He also has a special handshake he does with his friends and is commonly used when Gentaro makes a new friend.

Gentaro was looked after by his grandfather Goro Kisaragi after his parents died in accident years prior to the series. After reuniting with childhood friend Yuki Jojima, he tries to befriend loner Kengo Utahoshi, who goes out of his way to avoid him. When he slights Miu Kazashiro, Shun Daimonji begins to deal out "punishment" until a strange creature Yuki identifies as a Zodiarts appears. Gentaro begins to fight off the monster until Kengo arrives in the Powerdizer exo-suit, managing to keep the creature at bay, but leaving him physically drained. Kengo and Yuki head to an abandoned part of campus where they enter a locker that transports them to a lunar base known as the Rabbit Hutch. He prepares to use the devices left behind on the base, until Gentaro appears, having followed them into the locker. Gentaro takes the device from Kengo, who is still too tired to fight back. Gentaro faces off against the Zodiarts, but Yuki shows up to advise him on how to use the device he stole from Kengo. Gentaro activates the strange belt, transforming him into Kamen Rider Fourze for the first time. With Kengo's instruction, Gentaro is able to defeat the Zodiarts, and he is begrudgingly allowed to keep the Fourze Driver in order to battle the Zodiarts menace. To cement his new friendship, Gentaro forms a Kamen Rider Club, with Yuki and Kengo as its first members while taking up the title Kamen Rider.

Gentaro is shown to become increasingly adept in using the Kamen Rider Fourze system as the series progresses. He is shown to only be able to use conventional fighting moves, and has to rely on Kengo's advice on which Astroswitch to use in battle situations early in the series. As he gets increasingly used to fighting the Zodiarts, he learns how to devise strategies on the fly (though they do not always work and Kengo still needs to be around most of the time) and is seen to be using and changing Astroswitches more often. He is shown to be very resourceful with the use of Switches as he learns how to utilize each one in unusual ways, such as using Limit Breaks of Launcher, Gatling and Fire Switches together to form a long range Limit Break finisher, and Limit Breaking the Rocket and Drill Switches twice when he cannot finish Scorpio off with just his usual Rocket Drill Space Kick. When he has difficulty with properly using a Switch, he will take the time to understand it as he did with the Hopping Switch, ending up capable of using it as a weapon instead of just a tool.

Kamen Rider Fourze
The arsenal of Kamen Rider Fourze is developed by the group known as the Over Space Technology Organization. The OSTO developed technology that enables its user to harness a mysterious form of energy called Cosmic Energy (コズミックエナジー, Kozumikku Enajī). After Gentaro flips the four Switches on the Fourze Driver, he pulls the lever on the side of his belt, which transforms him into Kamen Rider Fourze. Gentaro took the equipment to become Kamen Rider Fourze from Kengo after he followed Kengo. Fourze is based off a space craft and roughly the retired Space Shuttle. Gentaro tends to say "Space is Here!" (宇宙キター, Uchū Kitā) when transforming into Kamen Rider Fourze and says "Let's settle this once and for all!" (タイマン張らせてもらうぜ！, Taiman harasete morau ze!) before battle. Similar to his predecessors, Kamen Rider Double and OOO, Fourze uses combinations with the Astroswitches and their Modules. However, unlike the Gaia Memories and Core Medals, which need a certain combination to transform into different forms, only a few of the Astroswitches changes Fourze into a different form (known as 'States'). Kamen Rider Fourze has shapes on his limbs where the Modules attach: Circle for the right arm, Cross for the right leg, Triangle for the left leg, and Square for the left arm. The suit itself also doubles as a spacesuit, allowing Kamen Rider Fourze to spacewalk. It also has a hover pack, allowing Kamen Rider Fourze to hover in the air for a short distance. The Red-Eyed Man compares Kamen Rider Fourze's power to that of a gravitational lens, particularly on how the Kamen Rider influences both Astroswitches and Zodiarts Switches. After accepting the title of Kamen Rider, he often names his attacks with "Rider" before it.

States
﻿Kamen Rider Fourze's forms are referred to as States.

Devices

 * Fourze Driver - Transformation device
 * Astroswitches - Fourze's (normally) small devices that allow him access to that Switch's Module when activated in the Driver
 * NS MagPhone - Fourze's cellphone-like gadget that allows the transformation into Magnet States
 * Elek Module Billy the Rod - Fourze's sword-like weapon that is used in Elek States through the Elek Switch
 * Fire Module Hee-Hackgun - Fourze's gun/flamethrower/fire extinguisher-like weapon that is used in Fire States through the Fire Switch
 * Cosmic Module Barizun Sword - Fourze's broadsword/spear-like weapon used in Cosmic States

Vehicles

 * Machine Massigler - Fourze's Rider Machine
 * Powerdizer - An independent support vehicle to assist Fourze.

Quotes

 * How can I befriend the entire school if I can't befriend scum like you? - say Gentaro to Kengo
 * Space is HEEEEEEEERE!! Kamen Rider Fourze! Let's settle this one on one! - Before battling against Zodiarts.
 * I am Gentaro Kisaragi! I'm the man that will make all students become my friends - Gentaro when introducing himself.

Trivia

 * Fourze's Magnet States is similar to Kamen Rider Gatack's Masked Form.
 * The Barizun Sword is similar to the Blay/King Rouzers used by Blade from Kamen Rider Blade.
 * The Cosmic States has the touch-screen similar to the K-Touch from Kamen Rider Decade.
 * His personality is similiar to that of Kenta Date(MegaRed) from Denji Sentai Megaranger, as they are both carefree high school slackers.