Great Leader

The Great Leader (大首領, Daishuryō)is the primary antagonist of the Showa Era Kamen Rider Series.

Name
As the Great Leader's origins are unknown, so is his true name. He is referred to only by his titles by both his subordinates and the Kamen Riders. In Kamen Rider Spirits (which has an alternate version of Birth of the 10th), he is given the name JUDO.

Abilities
As the founder and leader of the first ten organizations the Kamen Riders fought against, he has complete command over them and its members.

Forms
The Great Leader possesses many forms seen throughout the ten series. Most of his forms usually involve skulls or cyclopses.
 * The first form of the Great Leader when he ran the Shocker organization had a cyclops head under a mask full of snakes which was worn under a red hood similar to one of the KKK. He self-destructed in a failed attempt to destroy Kamen Riders 1 & 2. His identity in the movie reboot was never revealed.
 * The second was the Great Leader of Destron who was a skeleton destroyed by V3 but apparently it was only a decoy as inside the skull was a tape recorder.
 * His third form was that of Satan Bug, the Leader of Black Satan and was destroyed by Stronger.
 * He reappeared as the Delza General, a gigantic rock like soldier that tried to destroy Riders 1 through Stronger. The Seven Riders flew inside of him to discover he was actually an alien cycloptic brain who then self-destructed in an attempt to destroy the Seven Riders.
 * The Great Leader reappeared in the last three episodes of New Kamen Rider as a giant Boss Dragon of Neo-Shocker. He was destroyed by Riders 1 through Skyrider, who appeared to sacrifice themselves to destroy the Great Leader. It's later revealed that they survived as they assisted Super-1 in the Kamen Rider Super-1 film.
 * He reappeared near the end of Birth of the 10th! Kamen Riders All Together!! as a giant skull with big glowing white eyes to laugh at Riders 1 through ZX.
 * It is possible that the three faced alien head, Lord Crisis of the Crisis Empire is the Great Leader as he is voiced by the same voice actor and has stated to have fought the previous Showa Kamen Riders before.
 * In Kamen Rider Spirits, JUDO the Great Leader is shown either as a giant silver skull or a gold version of Kamen Rider ZX called Susanoo (named after the Shinto Kami of Storms and the Ocean) with the ability to change into the previous Showa Riders. He has his own language and can speak to people telepathically.

Part in the Series
The Great Leader has usually been away from most business involving the Kamen Riders, only appearing during the final parts of the show. He is constantly destroyed but always comes back up until Birth of the 10th or BLACK RX depending on the identity of Lord Crisis.

In the Heisei Era movie, Kamen Rider Decade: All Riders vs. Dai-Shocker, Kamen Rider Decade was the Great Leader of Dai-Shocker until he was overthrown by Shadow Moon, but neither of them are the original Great Leader.

Trivia

 * The Great Leader's form, Susanoo and its ability to change into the previous Showa Riders is probably an allusion to Kamen Rider Decade's ability to change into the previous Heisei Riders.
 * In addition, Decade was the Great Leader of Dai-Shocker prior to being overthrown.