Gundam RX-178, Mark II

The RX-178 Gundam Mk-II is a mobile suit introduced in the anime Mobile Suit Zeta Gundam as the successor to the iconic RX-78-2 Gundam. Developed by the Titans, the Gundam Mk-II represents a significant technological leap as the first mobile suit to incorporate the innovative movable frame concept. Unlike traditional designs where the frame primarily serves as a structural skeleton, the movable frame integrates vital mechanisms such as actuators and control systems directly into its structure, excluding weapons, armor, and propellant tanks. This groundbreaking approach enhances the suit's agility, responsiveness, reliability, and energy efficiency, making it far more advanced than earlier models.

A distinctive feature of the Gundam Mk-II is the exposed movable parts in its legs, reflecting the design philosophy of prioritizing mobility over heavy armor. At the time, it was believed that no armor could adequately defend against beam weaponry, so the focus shifted to weight reduction and increased maneuverability to evade attacks rather than relying on heavier protection. This lightweight, agile design philosophy made the Gundam Mk-II a formidable presence on the battlefield.