Belonging to the era of the Age of Paradise, Niniu comes from a tribe of minstrels who use songs to heal people's hearts and is the last surviving member of them.
She wears a headband and has long, blond hair that she wears into a pair of braids.
Although being mentioned by others as one without magic ability, she is able to hear the pain and distress of others, that will lead her to trace them. E.g, Ruruta Coozancoona. Her song is able to soothe him.
As the statue of the soul of destruction she gains absolute power. Her power is so great that Hamyuts Mesata, a person conditioned to enjoy death, actually experienced a fear of dying when facing her.
Initially, she hears Ruruta's voice and wants to save him from his pain and suffering. After falling in love with him, she mentioned that she wanted to save the world that she loves - a world where she is able to have lived and meet Ruruta.
However, she was lied to and clobbered to death by Vooekisal and his retainers. As she lay buried and dying, Orntorra appeared to her and convinced her to become the statue of the soul of destruction, an incarnation of the god of the future. Niniu accepted and attained control of endless beasts of destruction.
As the core of destruction, she was defeated by Ruruta during the fight against the Beasts of the Final Chapter. Lascall Othello withdrew her book from her statue and offered it to Ruruta, who had forgotten her due to drinking from Argax, a war machine of the past with an ability to selectively erase the memories of the drinker.
She appears at the end of the anime in Ruruta's nonentity entrails, since her book was eaten by him, and is determined to destroy the world. However, she is defeated at the end by the help of the Armed Librarians and the power of the people, and reunites with Ruruta.