Chisato Hasegawa serves as the school nurse at Hijirigasaka Academy, distinguished by her dark hair, green eyes, a mole beneath her left eye, red round glasses, and a voluptuous figure. Her professional attire typically includes a green turtleneck, black mini-skirt, cross-garter stockings, and a white lab coat she wears to signify her role as an educator. Casual outfits reflect an adult appeal, ranging from winter coats and scarves to summer flare skirts, while private wear consists of sheer silk baby dolls. At the pool, she wears an extremely revealing green sling bikini. Her goddess form, Afureia, possesses golden hair with blue highlights, blue eyes, a golden aura, and wings of pure light.

Her personality blends wisdom, mystery, and care, often advising students on personal matters despite an initial lack of romantic experience. She forms a deep attachment to Basara Toujou, evolving from mentorship into a secret romantic relationship marked by sexual openness and acceptance of his advances. This bond reveals her capacity for jealousy when Basara focuses on other girls, leading to teasing or punishment. She exhibits fierce anger against threats to Basara, particularly when Ornis attempted to steal his Banishing Shift. Over time, she embraces masochistic tendencies, finding pleasure in her descent from divine status to become Basara's submissive partner.

Originally the high-ranking goddess Afureia among the Ten Gods of the Divine Realm, she is the younger cousin of Raphaeline, Basara's biological mother. Fifteen years prior, she witnessed Raphaeline's punishment for bearing Basara, a hybrid child, and blamed herself for inaction. To honor Raphaeline, she transported Basara to the human world, entrusting him to Jin Toujou. With two allied gods' aid, she relinquished her divine position, had her powers sealed, and adopted the human identity "Chisato Hasegawa" to watch over Basara secretly.

Initially, her sealed powers limited her abilities, though she remained formidable—capable of restraining Basara barehanded during his Brynhildr rampage. She could temporarily access goddess strength to protect Basara, risking breaking her seal. Her divine capabilities include manipulating time within barriers, such as compressing a year and a half into one human night, and granting blessings that confer resistance to magic, memory alteration, illusions, and energy blasts. After forming a Master-Servant Vow with Basara in Volume XII, her full powers are restored. This vow creates a maternal link among Basara's pregnant partners, suppressing pregnancy ailments and synchronizing childbirths. Additional abilities include bestowing godly contracts, teleportation via Banishing Shift, and immense stamina evident in prolonged sexual encounters. Her non-combat skills encompass medical expertise and significant charisma.

Her romantic involvement culminates in the Master-Servant Vow ritual in Volume 12, conducted within her subconscious while Maria maintained a protective barrier. The ritual involved bondage, gang rape by Basara's clones, and dual penetration, with her physiology enabling hymen regeneration and lactation during intercourse. The vow balanced the elemental alignment of Basara's existing contracts—adding her light attribute to offset three dark-aligned demons and two light-aligned heroes. Post-vow, she regained her Ten God status and became pregnant. The maternal link protected her unborn child during sexual activity. She later agreed to Basara's request to spare the antagonist Shiba, intending to subjugate him via a contract exploiting Basara's zero-dimension banishing ability.

By the series' conclusion, she is integrated into Basara's household as one of his eight wives, pregnant with his child alongside the other heroines. Her role expands to domestic support, participating in household dynamics and strategic discussions concerning threats like Shiba. This completes her transition from a distant guardian to an active member of Basara's family and battle harem.