Tomoe Saotome

Tomoe Saotome 「早乙女 巴, Saotome Tomoe」 is Yoichi Saotome's older sister, who was killed by Lacus Welt prior to the manga.

Appearance
Tomoe had green eyes,and long brown hair, collected in two pigtails, with a forelock, and he had freckles. She wore a loose pink sweater with ruffles over her hips. She wore a short blue skirt and white knee-high socks.

Personality
She spent the last seconds of her life hiding her younger brother under a bed. She protected him and appeared to care about him.

History
Before of the apocalypse, Tomoe lived a normal life, with her parents and little brother.

After the Apocalypse is began, and following the death of the parents, Lacus Welt and René Simm hunted down surviving human children to feast on. She hid her brother under a bed but did not have time to hide herself. Lacus entered the room, grabbed her by the throat, and drank a great deal of her blood, even letting quite a bit spill onto the floor. He dropped her fresh corpse to the ground with a thud.

René informed Lacus that they were being called to HQ, so they left. Yoichi Saotome watched everything from under the bed as his sister's blood continued pooling out on the floor in front of him. It is not known what became of the body, and her place of burial is unknown.

Story: LN
???

Story: Manga
Tomoe first appears in chapter 2. Yoichi has a flashback as he tells Yu that he wants to become a soldier in order to avenge his sister, who was killed by a vampire while protecting him.

She reappears in chapter 7. During Yoichi's contract ceremony, Tomoe's death is replayed in front of him. She is left lying unceremoniously on the floor, bleeding and lifeless as her empty stare meets with his. She then speaks right to him, letting him know that she is showing him memories of his past. The demon had apparently taken the form of his sister, likely so as to wound his heart in the most wicked way available.

Standing in the same white void of his mind with the his demonic sister, Yoichi is told that the demon has found him wanting. There are no particularly strong feelings in his heart that the demon found appealing, and she feels that he simply is unworthy to command her power. It is then that the demon approaches him, threatening to possess him so that she can simply avenge Yoichi's sister in his place. With no apparent willpower to resist, Yoichi is taken and the demon awakens in control of his body, in the underground ceremony chamber.

Trivia

 * Tomoe 「巴」 means "Turning" or "Circular". It also is a Japanese abstract shape described as a swirl that resembles a comma or the usual form of a magatama. The tomoe is quite similar to the yin-yang symbol symbol for balance. The tomoe is made up of interlocked flames resembling tadpoles. Those three flames symbolize humanity, heaven and earth - the three foundations of Shinto philosophy.
 * Saotome 「早乙女」 means "Young Maiden".
 * In the light novels, it is confirmed she and her brother are also results of the "Seraph of the End" experiments the Hyakuya sect undertook.
 * If she were still alive she would have about 18-19 years.
 * Her parents are both dead from the virus.

Manga

 * "Yoichi! Don't come out from under the bed no matter what, okay?"--Tomoe Saotome's final words to her brother before being killed by Lacus Welt, Chapter 2, "Humanity After the Fall"