Onikiri (鬼切) is a servant of Mikage Shrine known as the onibi-warashi (鬼火童子 Translation: Will-o'-the-Wisp Child). She serves Nanami with the help of Kotetsu.
She is normally a miniature shrine spirit with a girlish mask on that has closed eyes with medium-sized lips and girlish mask hair. Onikiri dons a plain, white kimono with fire-ish looking designs on the end sleeves and kimono. She also dons a brown-grayish bow on her kimono, and just like Kotetsu - she is barefooted. In Kamisama Kiss 2 Episode 4, it is shown that, with the power of Lucky Mallet, she grows significantly taller with all of her features including the kimono, bow, and mask.
During her time as a grown shrine spirit (also in Kamisama Kiss 2 Episode 4), it is shown that her breasts have grown along with her body, stating that she is a female.