Niko is the younger of a pair of twin zashiki-warashi spirits who appear in the anime and manga series Hōzuki no Reitetsu. She is brought back from an abandoned building in the human world by Hōzuki, the chief deputy of Hell, and becomes part of his household alongside her elder twin sister, Ichiko. Niko is visually distinguished by her short white hair and pristine white kimono. She is virtually inseparable from her sister and the two are often shown together. As a zashiki-warashi, a type of yōkai traditionally believed to bring good fortune to the homes they inhabit, Niko embodies a playful and innocent demeanor. Her motivations are simple: she enjoys the comfort and safety of her new life in Hell and adores Hōzuki, whom she regards as a father figure. In the story, Niko serves as a supporting character, adding both comedic and heartwarming moments through her interactions with Hōzuki, her sister, and other residents of the underworld. Her presence highlights Hōzuki’s unexpectedly nurturing side, as he takes on the role of caretaker for the twin spirits. Niko’s notable abilities are those typical of a zashiki-warashi, including the capacity to bring good luck and the ability to appear and disappear at will, though she rarely uses these powers in a plot‑driven manner. Her character does not undergo major development; instead, she remains a consistent, cheerful presence throughout her appearances in the second season of the anime and its OVAs.