Eto Yoshimura (芳村 愛支エト, Yoshimura Eto) is the founding leader of Aogiri Tree, having formed the organization in the decade between her original rampage and the beginning of the series. While speculated by many to be the One-Eyed King, she claims that this is not the case.
Instead, she is the One-Eyed Owl (隻眼の梟, Sekigan no Fukurō), the half-human and half-ghoul daughter of Yoshimura and Ukina. Her human identity is Sen Takatsuki (高槻 泉, Takatsuki Sen), a best-selling horror novelist mentioned throughout the series.
After the Third Cochlea Raid and her defeat by Kichimura Washuu, she was captured and used as the main body for the Taxidermied Owl (詰めの梟, Tsume no Fukurō). She managed to retrieve herself from the body and returned to life.