In the anime
Karasuma Chitose is a sickly girl who joined the Galaxy Angels by request. Despite a polished and loving manner, she is actually counterproductive socially and quite bloodthirsty at times.
For most of her first 17 years of life, Chitose has been hospitalized for an incurable illness. Having no friends, she would stay in her room at all times watching through the window healthier people play outside and counting the leaves on a nearby tree. As an attempt to cheer her up, the Angels paid her a visit, during which she collapsed and asked to be one of the Angels before she dies. Her request was granted.
Once among their ranks, however, Chitose’s tactlessness failed her attempts to make friends and led to her being shunned by most of the Angels. Feeling rejected, she vowed to destroy the Angels and joined the rival Galaxy Twin-Stars as part of her vengeful plan. Thus begun a one-sided antagonism between Chitose and the Angels, as Milfeulle still considers her to be a very good friend and the others having either forgotten who she was or became indifferent. She would later be reassigned back to the Angels and would try to be their friend again as well as destroy them.
Although generally a nice and sweet girl, Chitose vacillates between wanting to make friends with the Angels and wanting to kill them. Fortunately, her desire for revenge is hampered by ineptitude and what seems to be bad luck, often inflicting serious harm upon herself rather than others. Unfortunately, her ability to make friends is also mired by ineptitude and bad luck, also resulting in self-injury as well as a renewed determination to kill. In the end, she rejoins the Angels.
After her service in both the Galaxy Angels and Galaxy Twin-Stars, Chitose stayed in the military as an accountant at age 21. Buried in paperwork, her life has (relatively) never been more miserable.
In the manga
She is the newest member of the Angel Troupe. She was found drifting in space in an escape capsule, she was the only survivor of a ship that was destroyed. Chitose also lost most of her memory when she comes out of the capsule. With the help of the angels and Takuto, she is able to slowly recover her memory. Because Takuto wants Chitose to help her regain her memory, she slowly starts to have a crush on him. The other Angels slowly become concerned of Milfieulle and Takuto's relationship, but Milfie assures them that it's no big deal because she wants Chitose's memory to return completely.
However, in volume 2, it is revealed that Chitose has unwittingly been mind-controlled by Noa all along. Noa tries to make Chitose kidnap Prince Shiva, but Chitose regains enough of her own mind to kidnap Takuto instead.
