Set in a fantasy world with shape shifting Dragon kings and their warriors. They terrorize the humans, and kill those with magic.
The protagonist is the great-grandson of a powerful warlock. He finds out that he has magic, and fights with it to save his new friends, the Griffin, Blackhorse (I think that's his name), some creepy necromancer who is immortal, and Gwen (fellow sorceress), along with the kingdom that the Griffin rules in.
They fight the protagonist's father, the leader of the Dragon kings, the king's Duke, and the creepy sorcerer, who has a curse (when he dies, he changes side from good to bad, or bad to good). I have no clue what this is called, but I want to find out, since I'm out of things to read.