Yotsugi Ononoki (斧乃木 余接, Ononoki Yotsugi) is an emotionless human corpse tsukumogami and the shikigami familiar of Yozuru Kagenui.
She's a somewhat unique take on both of the terms that define her, as tsukumogami are normally described as tools that have come back to life after years of neglect, and shikigami are typically depicted as being spirits or ghosts that are bound to an onmyouji master. In her case, she's a corpse that was likely once used as a "tool" and neglected but brought back to life, and a shikigami in the sense that she's a "spirit" that is bound to her master.