Urga

Urga is the leader of Nova Shocker and the main antagonist of the movie Kamen Rider 1.

Kamen Rider Ghost
Witnessing Yamaashi-Roid's destruction and failure to revive Ambassador Hell, Urga vowed to give rise to a new Shocker, scoffing at the organization he was once a part of.

Kamen Rider 1
Urga and Nova Shocker attempted to kidnap Mayu Tachibana, as she held the Alexander the Great Eyecon which they could use to conquer the world. Opposing them were the original Shocker, led by a revived Ambassador Hell, and Kamen Riders 1, Ghost and Specter.

Though Ambassador Hell had captured Mayu, Urga and his forces were led to the spot where he was trying to extract the Eyecon by a defecting Ganikomol. He succeeded in obtaining the Eyecon and seemingly killing Takeshi Hongo before returning to the Nova Shocker base.

Specter and Ghost later both arrived at Nova Shocker's base, but were unable to withstand Urga's new power granted to him by the Alexander The Great Eyecon. However, Urga soon begins to be overtaken by the Eyecon's power and kills Igura when she attempts to convince him to give up the power. He and Buffal fight Ghost and Specter until Ambassador Hell shows up and forms an uneasy alliance with them to stop Urga. However, they are still no match for Urga and the Alexander The Great Eyecon's power, at least until Takeshi Hongo shows up.

With assistance from Ambassador Hell, Ghost and Specter are able to perform a Double Drive Omega Kick to shatter Urga's sword projection before Kamen Rider 1 finishes him off with a Rider Kick.

Legendary! Riders' Souls!
Urga was later revived again alongside his subordinate Buffal by the power of the Alexander The Great Eyecon, but was destroyed again by Kamen Rider Ghost with a Rider Omega Drive Kick.