Rouran, titled Rouran the Azure, stands as one of the Four Kings beneath Nyanma, the primary antagonist commanding the Jyarei Monsters. He commands a high-ranking position within Nyanma's forces, specializing in the infiltration and corruption of Novel Worlds to advance Nyanma's objective of collapsing Mugen. Rouran embodies a cunning, ruthless, and strategically aggressive personality, showing no hesitation in targeting both combatant and non-combatant members of the Eto Rangers to achieve his goals. His approach prioritizes efficiency with lethal precision, establishing him as a persistent adversary.

Rouran brandishes a black laser blade akin to Bakumaru's lightsaber, unleashing waves of dark fire in combat. He also masters advanced disguise capabilities, enabling him to impersonate characters within Novel Worlds to evade detection and manipulate story events. This skillset allows him to embed deeply into corrupted narratives, complicating the Rangers' missions to identify and eliminate Jyarei threats.

His operational pattern centers on direct confrontation with the Eto Rangers, specifically targeting Bakumaru as a recurring foe. Rouran employs psychological manipulation and ambushes, leveraging his disguise proficiency to exploit the Rangers' trust in story characters. Among Nyanma's subordinates, Rouran is noted for coming closest to the complete elimination of the Eto Rangers, highlighting his effectiveness.

Rouran's relationship with Nyanma is defined by unwavering loyalty; he executes her commands without question. This dynamic positions him as a key enabler of her campaign against Mugen and the Novel Worlds. His role persists as a consistent high-level threat throughout the conflict, demonstrating no significant redemption or deviation from his allegiance to the Jyarei cause.