Neos Gold is the series' primary antagonist. A machine-like life-form created by Big Gold's computer terminal, she refers to Big Gold, Iczer-1's nemesis, as her mother, and has indeed inherited every single bit of Big Gold's malevolent personality.

In the very beginning of the series, she engages Iczer-1 in an epic battle that ends in a stalemate, with both combatants exhausted and badly wounded. Deciding to postpone the finish of their battle until both of them have recovered, Neos declares to Iczer-1 where she has chosen to finish their battle: Earth. She then sends her four generals to Earth, in order to wipe out any resistance before her arrival. Neos hacks into every computer network on Earth, and makes her presence known to humanity, before launching a preemptive attack that wipes out more than half of Earth's military in one stroke. In just five minutes, Neos wipes out nearly two-thirds of humanity, and reduces every major city on Earth to ruins.

Neos is extremely cruel, and shows no mercy to those who fail her, even her generals; after Fiber is defeated by Iczer-3, she executes Fiber herself, then assigning Insect the task of wiping out Iczer-3. After Insect is killed in battle, Neos appears to Iczer-3 herself, and steals the Iczelio Energy from Iczer-Robo, rendering it useless in battle. She then uses this energy to create Atros, an clone of Iczer-3. As an added insurance policy, she also resurrects Iczer-2, in an effort to guard against interference by Iczer-1.

In the final episode, after the three Iczers lift Neos' massive body into space and destroy it by combining their powers, Neos launches a final desperate attack against the three unconscious gynoids. However, before she can land a fatal blow, she is slain in battle by Iczer-3, thus ending the reign of terror she unleashed upon the Earth.