Heavy Knight Gundam GP02 stands as the Dabat Kingdom's strongest knight at the story's outset. He initially serves as superior and mentor to Knight Gundam GP01, his squire. This dynamic shatters when the Neo Zeon Clan invades and the Holy Machine Soldier Gunrex selects GP01 as its pilot over GP02. GP02 vehemently objects to GP01's selection, leading to his capture by Neo Zeon forces. During captivity, he succumbs to possession by the malevolent entity Sieg Zeon. This transforms him into Atomic Gundam, becoming the Neo Zeon Clan's foremost knight. As Atomic Gundam, he pilots the formidable machine soldier Zamled Chimera and spearheads the assault against his former homeland, the Dabat Kingdom. His actions directly contribute to the fall of Dabat Castle, forcing Queen Nina and others into flight. His path marks a descent from honored protector to instrument of the kingdom's destruction. While some adaptations depict GP01 beginning as a full-fledged knight rather than his squire, the core narrative of GP02's objection to GP01's selection, subsequent capture, possession, transformation into Atomic Gundam, and role as antagonist remains consistent.