Great Leader of Shocker

The Great Leader of Shocker (ショッカー首領) is the mysterious high ruler of the criminal organization Shocker, and the first incarnation of the Great Leader. After the destruction of the original Shocker, he formed an alliance with the Geldam organization and became the Great Leader of Gel-Shocker (ゲルショッカー首領). When he and Gel-Shocker was finally defeated by the Double Riders, he went on to resurface and become the Great Leader of several more evil organizations.

Appearance
The Great Leader's appearance remained hidden for nearly the entire series, however he made his first physical appearance in episode 34 briefly in a video footage. In his physical appearance, the Great Leader wore a red hood that resembles the hood worn by the Ku Klux Klan and a black cloak. Over the course of the the Kamen Rider series in the Showa Era, the Great Leader took on several forms and personas.

History
His ultimate goal is to turn the entire human race into kaijin under his rule in order to unite the world as one being. He orders his subordinates via speakers on Shocker's emblem to destroy Kamen Riders Hongo and Ichimonji who are the obstacles of his conquest. The two riders were able to severely weaken the Shocker organization by eliminating most of their key figures (Colonel Zol, Doctor Shinigami and Ambassador Hell), this forced the Great Leader to reform Shocker by allying himself with General Black of the Geldam organization, thus creating Gel-Shocker.

Seeing that old members of Shocker were considered unfit for the new organization, the Great Leader had them all killed one by one. All Shocker secret bases were self destructed and the remaining Shocker soldiers were killed. The Riders were able to defeat Gel-Shocker forces and its kaijin's, including General Black. The riders were able to locate Gel-Shocker's headquarters and finally confronted the Great Leader himself, the two riders uncloaked the Great Leader only to reveal that he is actually a Cyclopean medusa. He sets off the headquarters' self-destruct system in a final attempt to kill the riders, but only resulted in him being killed instead and the two riders escaping, therefore ending Shocker's reign of terror. Or so they thought...

Remergences
Shortly after, the Great Leader resurfaced as the Great Leader of the Destron organization. Which resulted in the Double Riders creating the third Kamen Rider, V3. He would go on to create several more evil organizations to menace the ever-increasing amount of Kamen Riders. His last known appearance was as the Generalissimo of the Badan Empire, who disappeared shortly after he made himself known to the ten veteran Kamen Riders. He may have also been the Grand Lord Crisis of the Crisis Empire who was destroyed by Kamen Rider Black RX.

OOO, Den-O, All Riders: Let's Go Kamen Riders
The Great Leader makes a return in the movie OOO, Den-O, All Riders: Let's Go Kamen Riders, serving as the film's main antagonist. During a small conflict between the characters of Kamen Riders OOO and Den-O during their time travel in Japan during the 1970s while hunting the Imagins, General Black discovered a Cell Medal that was accidentally dropped by Ankh during the conflict. General Black gave the medal to the Great Leader which he combines with the Shocker medal in order to create Shocker's most powerful kaijin, Shocker Greeed. The kaijin was able to defeat both Hongo and Ichimonji, thus causing a time paradox that created a world where Shocker reigned supreme. Various evil organizations that would had manifested in the normal timeline after Shocker's destruction later affiliated with Shocker and the Great Leader such as, the Delza Army, the Crisis Empire and the Government of Darkness. Shocker also gained control of both Hongo and Ichimonji via brainwashing.

OOO and Den-O returned to 1970s Japan in hopes of stopping Shocker Greeed from being created and returning the timeline back to normal. The Great Leader was confronted by the Riders, but was able to create Shocker Greeed and the kaijin manage to take down the Riders. Having failed to restore the timeline and the DenLiner destroyed, the Riders retreated back to the Shocker-ruled future and decided to confront Shocker, but were overwhelmed by the various kaijin forces. As the Riders were about to be publically executed, Hongo and Ichimonji (having been faking their brainwashing in order to wait for the right time to fight Shocker) summoned all the other Riders and were able to defeat the kaijin army.

The Double Riders have a rematch with Shocker Greeed while the other Riders rushed toward Great Leader. Shocker Greeed is destroyed by the Rider Double Kick before Ankh takes the Shocker Medal. When the Riders are overpowered by Great Leader's attacks, Ankh convinces OOO to use the Shocker Medal and an Imagin Medal from Momotaros in combination with the Taka Medal. With the three Medals, OOO changes into Tamashii Combo and destroys Great Leader with the Tamashii Bomber. The attack, however, unleashes Great Leader Colossus - the true form of Great Leader, who throws fireballs at the Riders and consumes the other Shocker leaders in an earthquake. The Riders are joined by Kamen Rider Birth and all of the extra Riders to battle the new menace. All of the Riders jump into their motorcycles to execute the All Rider Break, destroying Great Leader Colossus once and for all.

Super Hero Taisen Otsu
to be added

Great Leader of Shocker (Kamen Rider The Next)
The Great Leader makes a cameo appearance in the film Kamen Rider The Next via speaker from the Shocker symbol. He commands the Shocker group led by Scissors Jaguar to run the Nanobot Operations in Japan. By the end of the film, the Great Leader remains at large.

Kamen Rider video game
The Great Leader of Shocker appears in the PlayStation Kamen Rider video game. He is the boss the player fights in the "Kamen Rider Story" after defeating all the Shocker and Gel-Shocker kaijin.

Portrayal
In Kamen Rider, the original series, the Great Leader of Shocker was voiced by Gorō Naya (納谷 悟朗). He would go on to voice the Great Leader's various incarnations in the Showa Kamen Rider Series: the Great Leader of Destron, the Great Boss of Black Satan, the Great Boss of Delza Army, the Great Boss of Neo-Shocker, and The Generalissimo of Badan.

Gorō Naya also voiced the Kamen Rider The First reboot version of the Great Leader in the movie Kamen Rider The Next.