Spirits of Shadowfire Series

At the exact time of two shooting stars, two children were born. Eons ago, it was prophesied that they would become visible when the enveloping darkness came to subdue the universe and its sentient nemesis, attacking the outer regions of the solar system. Their calling is at hand. Their old teacher Irises the Sleeping Tiger knows he must prepare the children for the battles ahead.
The race has begun!
It must be good because Mark is reading it, and he never reads (Chelsy Cliff, 7).