Nia Honjou

The 9th Spirit, the second one confirmed in the world, has gray hair and turquoise eyes, and appears to be between 18 and 19 years old. She sometimes gives people strange nicknames and calls Shido "boy." Ten years ago, she became a manga artist under the pen name Soji Honjo, but was captured by Ellen five years ago and has been detained as the top-secret "Material A."

She was imprisoned in an underground facility on Neril Island, a location not marked on Pacific maps and where numerous human experiments were conducted by DEM. She underwent various experiments and torture, nearly leading to mental breakdown, but did not invert. Later, a micro-manifestation device was implanted in her brain to erase her memories of torture, and she was transported to a DEM-related facility in Japan. During transport, she resonated with Shido's rampage, broke the container holding her, and escaped. Weeks after her escape, she appeared before Shido by chance to thank him for creating the opportunity for her escape and offered him a chance to seal her spirit power.

Her existence had been mentioned before, but she is counted as the "9th Spirit" in the order of spirits appearing before Shido. Due to the abilities of Raziel, she became distrustful of humans, knowing their tainted aspects, which also led her to become fixated on the two-dimensional world. Later, she lost a battle with Shido and his group, acknowledged him, but this triggered a trap by DEM, and her erased memories resurfaced, causing her to invert. She was severely injured and inverted by Ellen and Artemisia's intervention, and her inverted spirit crystal was stolen by Westcott. However, she had slightly reverted from her inverted state just before, retaining some spirit power, which was sealed by Shido after Natsumi's healed her wounds, and Shido circulated their spirit power through Nia, saving her life.

Her identifier is . Her spirit gear, reminiscent of a nun's habit with a cross and a pen, is the nun-type spirit gear . The manifesting angel, shaped like a book adorned with a cross resembling a holy scripture, is . Her ability is omniscience. Except for the future, she can know anything she wishes about current events, who is doing what, etc., and everything is "fact." With the pen attached to her spirit gear, she can write in to control the future actions of the subject written about, manipulating them like puppets through "Future Inscription."

When inverted, the manifested demon king is a giant book . The writing in the book becomes automatic, and the writing speed increases, scattering pages from the demon king's body, increasing the number of moves and speed compared to before inversion, and it can also materialize the beings written in the book. It is unclear whether this change is due to the transformation into a demon king, but she can also know about historical alterations and can convey known facts as images to others. Since she is not fully integrated, "Future Inscription" cannot be used. She can create a space mixed with stories from around the world, called , and send people there.