Kyrie, a kind and diligent 16-year-old mute Holy Maiden, is unjustly exiled from the Geta Niiga Kingdom by the infatuated Prince Momok, manipulated by the jealous and self-serving Holy Maiden Hasrea. Abandoned in the dangerous Naraka Forest, Kyrie discovers a miraculous ability: she can understand the thoughts and voices of monsters, beginning with a mother bear (Kumako) and her cub (Kumakichi) whom she saves and names. Naming them causes them to undergo "Existence Evolution," transforming into larger, more powerful "Named Monsters." Unafraid, Kyrie finds joy in their fluffy forms and growing affection.
Kumako and the ancient Treant King reveal that Kyrie's family name, Iori, links her to the legendary "Holy Demon King" Eleonora Iori, a human who once understood and healed monsters. They believe Kyrie is her descendant or reincarnation. Guided to the desolate "Dead End" (formerly "Paradise"), Kyrie finds the forest's dying elder, Chatra, a legendary Fenrir and one of the "Holy Twelve Zodiacs." Using her divine healing power, Kyrie not only cures Chatra's old age but restores him to a youthful, human-like form. Chatra, deeply moved, confirms Kyrie's identity as the Holy Demon King's successor and offers her the "Ring of Water," a Holy Relic of the original Holy Demon King. Upon wearing it, Kyrie's healing power is amplified, instantly restoring the ruined church and garden, demonstrating her ability to repair inorganic matter and rejuvenate life.
Initially hesitant about using divine power for monsters, Kyrie's resolve solidifies after healing a hungry slime. She realizes that monsters, like humans, possess hearts and deserve compassion. Her internal thoughts, transparent to monsters, deeply move Chatra and Kumako, who pledge their unwavering support. Kyrie accepts her destiny as the Second Holy Demon King, vowing to create a world where humans and monsters can coexist peacefully.
Meanwhile, in the capital, Hasrea revels in Kyrie's presumed death, unaware of the public outcry against her. Priest Ion, Hasrea's superior and crush, confronts her, revealing that Kyrie was the true guardian of the city's peace, not Hasrea. Enraged by Ion's praise for Kyrie and his dismissal of her own abilities, Hasrea recklessly vows to prove her worth.
Back in the forest, Kyrie's "inauguration" is sparsely attended due to monsters' distrust of humans. However, she saves a pregnant Griffin, Sindura (another Holy Twelve Zodiac), from a difficult birth, earning her loyalty. Sindura then gathers many injured monsters, whom Kyrie effortlessly heals, even regrowing lost body parts, showcasing her seemingly inexhaustible power (which she attributes solely to God). Her compassion quickly wins over the wary monsters.
The narrative culminates when Kyrie intervenes in a conflict between hungry Red Caps and human adventurers led by Gaap. Her telepathy now extends to humans, allowing her to mediate. She heals both sides, astonishing the adventurers by restoring Gaap's (a beastman) lost ear and tail. This shared experience of healing and a communal meal fosters mutual understanding, reinforcing Kyrie's belief that coexistence is possible. Gaap, deeply impressed, resolves to report this "Queen" to his own monarch, signaling a potential shift in human-monster relations.
