OVA
Description
Yukina Himeragi is a petite teenage girl with a slender build, childish features, and an extremely cute appearance. She possesses shoulder-length black hair with a fringe framing her dark golden-brown eyes. Often seen in Saikai Academy's uniform with blue socks, her physique conveys acute tenacity. She carries a black bass guitar case holding her primary weapon, the Schneewalzer lance, an anti-demon spirit spear. Her attire adapts to events, including a cheerleading outfit during festivals or a turquoise maid uniform for Halloween.

Her background stems from a traumatic event at age six, nearly sacrificed to a Spirit Wolf by sorcerers. Rescued by the Lion King Organization, she underwent rigorous training alongside Sayaka Kirasaka under Yukari Endou's mentorship. This isolated upbringing fostered a unique worldview, interpreting everyday objects like golf clubs as weapons or pressure cleaners as flamethrowers. At fourteen, she was dispatched to Itogami Island as an apprentice Sword Shaman, tasked with observing and potentially eliminating the Fourth Primogenitor, Kojou Akatsuki, should he threaten humanity.

Personality-wise, Yukina blends naivety with tenacity. Generally soft-spoken and unassuming, her isolated past left her emotionally inexperienced, leading to frequent confusion, embarrassment, and defensiveness. Fundamentally kind, thoughtful, and protective, she safeguards those she cares about, even capable individuals. She develops romantic feelings for Kojou, experiencing jealousy when other women approach him. However, she channels this jealousy into protectiveness rather than bitterness, often befriending rivals and redirecting frustration towards Kojou through minor violence. She self-justifies her actions as his "observer" to cope with evolving emotions.

As a Sword Shaman and Attack Mage, Yukina wields supernatural abilities centered on her Schneewalzer lance. It enables offensive enchantments invoking "divine might" to smite spirits and defensive enchantments creating shields to expel calamity, utilizing divine vibrations to negate magic. Her high compatibility risks transforming her into a Faux Angel, granting flight and enhanced power but threatening her humanity; a ring from Yukari Endou mitigates this. Additional abilities include Divine Spirit Possession (borrowing spirit power at ego-loss risk), Shikigami Summoning for messaging or alerts, and Familiar Summoning, specifically Minelauva Iris inherited from Hektos. Her magical training is limited but strategically applied, including techniques like Pulsation for bare-handed magic amplification.

Her character development spans the series. Initially focused solely on observing Kojou, she becomes his first Blood Servant after activating his vampiric abilities, causing her blood to carry his scent. This bond deepens their connection, transitioning her from observer to trusted ally. She aids Kojou against threats like Natsuki Minamiya's guardian Rheingold and the rogue alchemist Kou Amatsuka, employing an enchanted meteoric iron knife in the latter conflict. Throughout events like the "Banquet of the Observers" and "Kaleid Blood," she navigates her role within Kojou's expanding circle, overcoming jealousy to collaborate with allies like Astarte and Kanon Kanase. Her resolve is tested in arcs like "The Broken Holy Spear" and "Kingdom of Valkyria," where she balances duty with personal loyalty, solidifying her place as Kojou's primary protector.

Notable trivia includes her physical measurements (B76-W55-H78), aerophobia, advanced education enabling English fluency, dislike of mayonnaise, and fondness for cats—especially cat plushies like Nekomatan. Her blood's scent remains indistinguishable from Kojou's due to their bond.