The StarChildren are a group of legendary heroes that were chosen by the heavens. Each of them have unique powers and gifts.
SPOILER WARNING--There are major plot details and endings in this article; such as character deaths.
The StarChildren in the Anime
The StarChildren have extra powers in the anime to make it more fantisized and cause young male fans of the new franchise to be in awe. In the anime, there is a lot less murder and violent features from the StarChildren--they are all heroes, but in the books a few of them killed there foes sometimes.
The most well known of the StarChildren are Sebastian, Sandie, and Bunny. Though there are less than 20 StarChildren most noted, the number of StarChildren or StarChildren Apprentices are infinite.
StarChildren in the Books
The StarChildren have more sin in the books and manga--most notably Fiona--for killing their enemies--instead of allowing them to live.
They are still heroes, but it is present that there is more scary content in the manga and books.
"Sebastian's fangs dug deeper--and the wolf let out a pitiful cry--then crashed on the ground; dead and bleeding."
There is also more perverted content in the books--like Fiona thinking Shark and Sebastian are perverts--for Sebastian walking in on Sandie when she was changing, which was entirely accidential, and Shark in the girl's side of the jacuzzi later in the first book--seeing girls in bikinis, which is NOT accidential. These parts are as bad as the adult humor gets in the books--being slightly perverted. It is not uncommon to see in the series.
There are some deaths of StarChildren in both the anime/manga--which deeply depresses fans.
Bunny didn't completely die off the series, but in the book series she had many deaths and revivals; including her first death, where she was hung after watching her family tortured and killed. That is the only death that was revealed so far.
Canine, like Bunny, didn't completely die off the series, but he had similar expieriences similar to Bunny's.
It is unknown if he is forever dead or only had a temporary death--but he had been torn to pieces by his enemy, Soke, and his death was avenged by Sebastian--whom beheaded Soke.
An evil StarChild that wasn't officially one of the StarChildren--but had the gifts just as one did. He was an Akita, and was beheaded by Sebastian.