Scarlet Hibiki leads the Gren Falcon Squad within the WSO's global Skull Force. She is a young woman of average height, characterized by long red hair and amber eyes. Scarlet consistently wears the standard Skull Force uniform, distinguished by a red scarf signifying her captain rank.

Her personality centers on discipline and morale within her unit. She commands respect from subordinates, including the notoriously difficult pilot Ken Kaido, who respects her. Scarlet adopts a mentorship role toward rookie engineer Tsubasa Yuki, offering guidance and comfort. She shifts into a stern, focused demeanor when enforcing discipline or confronting enemies.

Scarlet's combat and leadership capabilities are well-regarded in the WSO. She demonstrates proficiency with a whip to disable adversaries and exhibits exceptional piloting skills operating the Wingle support mecha. In the manga adaptation, she effectively evades attacks from the Mazinkaiser SKL and damages its Skull Pilder control unit during a confrontation.

Her narrative role diverges significantly between the OVA and manga. In the OVA, her involvement is limited, primarily appearing during the Skull Force's mission to deactivate the Gravity Curtain on Machine Island. She provides brief support to Tsubasa Yuki before their carrier breaches the curtain, after which she dies from a stray bullet fired by island mechanized forces. The manga substantially expands her involvement, positioning her as the direct superior officer to Death Caprice Squad pilots Ken Kaido and Ryo Magami. She regularly briefs them on missions, engages in occasional disputes, and actively supports their operations piloting the Wingle. Her death during the Machine Island mission occurs similarly to the OVA but carries greater narrative weight due to her established relationships.

Her key relationships include professional oversight of the Death Caprice Squad, mentorship of Tsubasa Yuki within the Gren Falcon Squad, and operational reporting to Skull Force commander Kojindani.