Doctor G is Destron's first general in a knight armor who originated from Germany and was given charge to oversee their operations in Japan. He is the leader of the Mechanical Army. He wields a battle axe, a short sword, and a knife. In the comics, his scorpion-shaped helmet could transform into a deadly scorpion, but this didn't happen on TV. Most of his monsters are cyborgs that are the same type as Destron Leader's cyborgs. Pronounced his enemy's name "Kamen Raaaaida V3!".

After numerous failures, Doctor G summoned the spirits of his dead, evil warriors to transform him into Kani Laser for his final battle with Kamen Rider V3. Despite putting up a valiant battle, he was destroyed by V3's V3 Kirimomi Hanten Kick.

Doctor G arrived in Japan after he was contacted by Great Leader of Destron who gave him orders to oversee their operations and to defeat Kamen Rider V3, Shiro Kazami.

Doctor G was responsible for the resurrection of Shocker's key figures (Colonel Zol, Dr. Shinigami, Jigoku Taishi, and General Black).