The Swords of Draconus: The Red Knight - The Realm of Magic, #5

'Woe to the House of Draconus for the blood they spilled. One day, the house will fall.'  PRINCE Tarquin Draconus sets out with his Moon Knights and the wizard Dru-Mak to locate his twin sister, a sha'tar, and the last two Amulets of Amalthea. All three amulets and the sha'tar are needed to release the immense power of the magical Gryfwd, a blade created by the ancient Drakons to restore the balance between good and evil.
Tarquin and his twin sister are the prophesized Dualta, born a thousand years earlier and brought to the future to slay the God of Chaos, Rabin Dranath. Rabin has murdered all but two members of the Royal House of Draconus: Sylvia, the Princess of the Summerlands, and Tanis, the young daughter of Tarquin's brother, the late King Thorston. But darkling shapeshifters are replacing everyone in positions of power throughout the land.
Rabin Dranath now controls the kingdom of Arkadia. An undead boy prince sits on the throne, and a bounty lies on Tarquin's head. With brigands, bounty hunters, dark gods, and a vengeful black dragon hunting for him, every step Tarquin takes will either lead him to victory or annihilation.