Eru has Klinefelter's syndrome (47, XXY) and because of that syndrome he is infertile, has week bone structure, has curvy body, has hypogonadism but isn't tall.
The mother of the family, Yuuna Hoshimori (星森 ゆうな), was really obsessed with cute and feminine things like the many dolls that she had so she wanted to have only one daughter to spoil and dress in adorable outfits (just like a doll). Unfortunatelly for her, she gave birth to twins: a female and a male. Even having one boy as a child, she decided to raise him like a girl.
Eru's twin sister is called Mimi, but her real name is Miko Hoshimori (星森 みこ). Mimi has Turner syndrome (45, X0).
Mimi and Eru are monozygotic twins, which means they came from the same zygotic cell. When the zygote was dividing to the 2-cell stage, there was a error that created one cell with 47, XXY and a second cell with 45, X0. The first cell originated Eru, a male, and the second cell originated Miko, a female.
They also have an older cousin named Kia.
Aaden King is the name of Eru's father; he is from Australia, which makes Eru and Miko mixed-race. The father came from Australia to Japan and he chose to live in Japan to create a family there with Yuuna. Since the twins were born in Japan and therefore have japanese nacionality, they were named with japanese names as well in order to keep the family's tradition.
Once the parents noticed the partially pink hair of the twins, they decided the name Mimieru wich comes from the word momoiro, meaning "pink".
Hoshimori, the family name, roughly means 'forest of stars'.
Digital artwork by Cari Rez Lobo drawn on June 10, 2013.
View it on DeviantART!