Hibiki Shikyouin is a first-year student at Paprika Private Academy and the grandchild of a chairman investor. Crowned "The Greatest Prince" after winning the "Mr. Universe World Prince of the Year" tournament, Hibiki presents a charming, princely persona perceived as humble and kind. This facade masks a cunning and manipulative nature willing to exploit others for personal gain. Hibiki is non-binary, as confirmed by a producer, adhering to no male or female category and self-identifying solely as "Shikyoin Hibiki." This stems partly from childhood experiences, including being mistakenly scouted as a male model and later adopting a boyish appearance to avoid recognition by Ajimi Kiki, who knew Hibiki with long, curly hair and used the nickname "Kurukuru-chan."

Childhood trauma underpins Hibiki's worldview: friends abandoned Hibiki after mistakenly believing the family lost their wealth, leading to deep-seated trust issues and a fear that relationships depend on continuous performance. This fosters a cynical rejection of friendship and altruism, embracing a Randian objectivist philosophy where only self-interested geniuses deserve to lead, believing this hierarchy benefits society. Hibiki fixates on finding the "Best Princess" to form an elite idol unit, initially dismissing ordinary individuals as unworthy. This drive manifests in the PriPara alter ego "Thieving Genius," who wears a distinctive black cloak, hat, and mask to steal other idols' coords using gadgets like a tommy gun or building-swinging tools.

Physically, Hibiki has fair skin, sharp lime-green eyes, and short, boyish silver hair. The voice remains consistently masculine-toned. Hibiki hates verbal tics—triggering violent reactions like shattering teacups—due to Ajimi's childhood influence, and loves theatricality, coding, hacking, and the concept of "Revolution." Hibiki enjoys deceiving others, particularly regarding gender presentation, and maintains high standards for skill and intelligence, dismissing those deemed "stupid."

Significant relationships include Falulu, initially pursued as "Princess Falulu" and later forming the unit Tricolore with her and Fuwari Midorikaze. Falulu uses the nickname "Maho-chan." Hibiki admired Fuwari's free-spirited nature but rejected her as a princess candidate for lacking refinement; their relationship strained when Fuwari declined the role but recovered in Tricolore. Ajimi Kiki's erratic behavior caused Hibiki to cut off childhood curls and develop the phobia of verbal tics. Andou, Hibiki's butler, assists in PriPara operations.

Character development occurs across media: Hibiki begins as a primary antagonist in Season 2, attempting to replace PriPara with CelePara and impose elitist ideals. After nearly destroying PriPara, exposure to others' kindness—particularly during the 24.5 Hour Live event—prompts a shift. Hibiki softens, forms Tricolore, acknowledges skill in rivals like Mirei Minami, and adopts a more collaborative outlook. While retaining mischievous tendencies and occasional regressive behavior, Hibiki evolves into a protagonist who values PriPara and protects allies, sacrificing to save Fuwari and facilitating Andou's return.

Iconic coords include the Brilliant Prince Cyalume Coord for performances, Military Look Coord for casual wear, Thieving Genius Coord for heists, and the Tricolore unit's PriParis of Flowers Rouge Coord. The surname "Shikyoin" incorporates "purple" (tying to Season 2's color theme), "capital," and "institution," while "Hibiki" means "echo," reflecting auditory motifs. Hibiki's birthday is March 27 (World Theatre Day), blood type is B, and chocolate cake is a preference.