As a sickly young girl Towa was fed the blood of a mermaid by her sister Sawa. Towa recovered from her illness but developed a deformed arm, resembling that of a Lost Soul's. Towa also stopped aging on the outside, but her internal organs all remained the same, aging naturally. When their father learned of what Sawa had done to her sister, he forced Towa to live in a cell underneath their house and to never come out. Many years passed and Sawa had a life of her own, getting married and having a child, while Towa lived alone completely cut off from the world except for her fiance, Dr. Shinna.
The Meaning Behind the Name
Towa is made up of two kanji meaning "ascend" and "harmony". Kannagi's three kanji mean "souless tree".
Sumi Shimamoto has had a ton of Takahashi related roles, including Kyoko Otonashi in Maison Ikkoku, Ten's Mother and Rara in Urusei Yatsura, Sue in Maris the Supergal and of course Nausicca in Nausicca of the Valley of the Wind.
Erica Shaffer is best known as a successful commercial actress. Some of her anime credits include Kanna and Mrs. Shiratori in Rumiko Takahashi Anthology, Lily in Spirit of Wonder, and Kaoru Satsuki in Amazing Nurse Nanako.