Sakura, the protagonist, is thought of as cute and helpless by boys who think they should protect her, but she's actually a martial arts expert and turns down guys who ask her out because they don't know the real her. Prior to the storyline, she found an old dog whose homeless owner had died a few months before the start of the story. She attempts to befriend the dog whom she promptly names "Dog". Her attempts are fruitless until Oogami comes. She is apparently an exception to Rei's fire and cannot be burned. Sakura disagrees strongly with Oogami regarding his views on people, specifically criminals, and that they are trash who need to die.
Sakura is later revealed to be the adopted child of the Sakurakouji family, and President Shibuya's biological daughter, thus she inherits his blood and is also a "rare kind", the ones with immunity to special powers and the ability to dispel them. Like a special power user, Sakura also has a Lost form: she takes a miniature form of herself, just like Shibuya. Before Shibuya gave her up to the Sakurakoujis, Sakura lived inside Eden's laboratory and met Ogami for the first time there. It's later revealed that during the incident in which Ogami's parents died, Sakura tore off Ogami's arm and thus forced him to graft the Emperor's arm onto his own to survive. It's unknown what exactly transpired in this incident, save for that many laboratory staffs died along with Ogami's parents. Although Sakura has long since forgotten about her time in Eden (even her acquaintances with veteran Eden agents like Hitomi and "The Seeking One"), this incident is deeply ingrained in her subconsciousness, and is the source of her determination to never let anyone die in front of her eyes.
Heike later reveals to Sakura that her mother is one of the 4 founders of Eden 100 years ago. The "Seeking One", when he speaks to her through a remnant of his soul left inside her body, reveals that she and Ogami are both connect to the mysterious "32nd of December", something that got him nearly killed by Eden when he tried to look into it.