The Reading Spot

Kushiel's Scion by Jacqueline Carey

This is the first of a new trilogy in this world, but this trilogy has to do with Imriel, Melisandre's son and also Phedre's foster son. Very good story, It is a great addition to the series/world. You have to read the other trilogy first before this one though, Kushiel's Legacy Trilogy.

Booklist, in their review has a great description, so I am going to use that.
Traitorous parents, the curse of Kushiel's blood in his veins, and the unspeakable crimes he endured while a child slave severely damaged Imriel. Feeling tainted and incapable of goodness, he fears he will misuse Kushiel's gift. Yet he is compelled to overcome the dark forces that shaped him. The love of Phedre and Joscelin, his beloved adoptive parents and Terre d'Ange's greatest champions, has helped him heal. He does an excellent job of comporting himself as a prince of the blood, third in line from the throne, until he turns 18. Then the conflicts raging within threaten to overwhelm him. Pushed beyond his limits by his first visit to Valerian House with his Shahrizai cousins and angry with the powerful, twisted desire that is Kushiel's legacy, in an impulsive moment he flashes up at Phedre--and changes his world irrevocably. He is now on his path to adulthood, first stop Tiberium. Traveling and living simply, he hopes to find himself.