Senna

Large amber eyes and a spiky purple ponytail define Senna at a glance, the tail bound by a ribbon she trades from yellow to red partway through her story. Off duty she favors a light brown shirt over a brown skirt with a maroon tie. When she shifts into her Shinigami self she wears the plain uniform of an unseated officer, cinched at the waist by a wide red ribbon.

Drawn to the color red and to any high vantage point, Senna is endlessly curious and rarely stays still, flitting from one distraction to the next. Stray fragments of a life she cannot place surface without warning, yet her default mood stays light and untroubled. Ichigo pegs her as headstrong, stubborn, and quick to speak her mind. Beneath the playfulness she is fiercely devoted to the people she cares about, ready to gamble her own safety to help Ichigo.

Senna first crosses paths with Ichigo and Rukia while cutting down a swarm of pale beings called Blanks in Karakura Town, unleashing her Shikai, Mirokumaru, to sweep them away with a tornado. She spends the following days dodging Ichigo's questions, unable to name her division or explain her patchy recollections. She is eventually exposed as the Shinenju, the memory core of the Blanks, sought by Ganryu and his Dark Ones, an exiled clan who mean to feed her into the Valley of Screams and slam the Human World and Soul Society together. Ganryu captures her, but Ichigo pursues, kills him, and pulls her free. To halt the two worlds from colliding, Senna returns the gathered memories to the Blanks, spending her own existence in the process and fading away after asking Ichigo to confirm that her name really is carved on a grave in Karakura.

Her Zanpakuto, Mirokumaru, rests as an ordinary red hilted katana and had been lost in the Dangai a century earlier when its owner was drawn into the Valley of Screams. Released with the phrase Call forth the Twilight, it takes the shape of a pointed staff whose ringed head conjures and steers whirlwinds. Senna also carries high spiritual power and fights like a gymnast, blending swift precise cuts with constant shifts of stance, uses Shunpo, and can slip out of her Gigai at will, the empty shell scattering into autumn leaves. As the Shinenju she commands the Blanks themselves.