Ryū Dollk serves as a high-ranking Dragon Empire warrior, commanding biomechanical forces under Empress Zara to conquer Earth and resurrect the evil god Jashin Drago. He possesses a strong sense of honor and dignity, consistently rejecting underhanded tactics and preferring fair combat despite his allegiance. His rivalry with the protagonist Ken Taiga, both wielding transforming biomechanical armors, fuels recurring conflict.

A distinctive dragon mark on Ryū's hand leads to recognition by Yui and Mai Kamishiro as their long-lost brother, a revelation Empress Zara simultaneously acknowledges. This discovery creates internal conflict and begins shifting his loyalties. During the Dragon Empire's devastating assault on Tokyo, Ryū intervenes to assist Ken Taiga, fighting alongside him against enhanced biomechanical beasts.

Ryū definitively aligns with the protagonists after Jashin Drago's revival. When Drago manifests as a multi-headed entity merged with Empress Zara, Ryū joins the final battle within an otherworldly dimension. He aids in freeing the captive Kamishiro twins and contributes to Drago's defeat through the combined efforts of the heroes and the newly awakened ultimate form, Liger Agama.

Concluding the conflict, Ryū Dollk chooses self-sacrifice to atone for his actions committed under the Dragon Empire, despite the potential for future redemption through aiding survivors. This act completes his arc from honorable antagonist to tragic ally.