Diamond Ryugu commands the Dragozaurs, an alien race consuming planetary life forces to fuel their quest for universal domination. She acts as the primary antagonist. For most of the narrative, only her eyes and an effeminate voice are perceptible, preserving mystery until her full reveal. Her true form is a colossal Ankylosaurus that breathes blue fire, featuring a humanoid warrior torso rising from its back, creating a centaur-like structure; this warrior form engages directly in combat.

Her operational strategy centers on delegation. She commands subordinates like Drago Wing, Gigano Dragon, Dark Dragon, and the Drago Clones to execute missions targeting Earth's life force. She rules with authoritarian control, punishing failures harshly, exemplified when she attacks Drago Wing with her breath weapon for questioning her orders. Diamond Ryugu strategically creates Drago Clones—genetic replicas of the Dino Knights—using the "Dark Crystal" as a power source for their production.

She initiates two nearly successful campaigns to harvest Earth's life force, abandoning her typically stationary command role only during these critical endgame phases. Her defeat manifests in two distinct ways: exposure to sunlight melts her physical form, and in a separate confrontation, neglect toward a subordinate entity known as "the Swarm" leads them to consume her as retribution. Following both defeats, she asserts her inevitable return, implying resilience or resurrection contingencies.