The Generalissimo of Badan is a giant skull that appeared after Ambassador Darkness's death. It disappeared sneering at the ten Riders. Dr. Kaidō said that it was the energy of an evil spirit.
Kamen Rider Spirits
In the manga, Kamen Rider Spirits, the leader is identified as Great Leader JUDO, JUDO has a Kamen Rider form called Susanoo, a golden version of ZX with the ability to transform into nine Shōwa Kamen Riders. He has his own language, which he can telepathically compel others to understand.
Heisei Rider vs. Showa Rider: Kamen Rider Taisen feat. Super Sentai
The Generalissimo of Badan reappears in this film as the main antagonist, taking the form of a giant tyrannosaurus fossil who's head that opens up to reveal a three-eyed skull. His goal was to open a portal to the underworld to release all of the previously defeated Kamen Rider villains and monsters. He is defeated when the Ressha Sentai ToQger in ToQ-Oh fuse with Kyoryu Red in Gabutyra and Kamen Rider Den-O in Den-Liner, combining into ToQ-Oh Kyoryuzin Feat. Den-Liner and destroy the Generalissimo of Badan.