Dorian Hawkmoon, The Runestaff - and the Black Jewel.

The Runestaff held all the secrets of the barren earth. The destiny of Dorian Hawkmoon, Duke of Köln, Eternal Champion, was forever bound by it. How was the Black Jewel to twist his fate?

Dorian regained consciousness with the Black Jewel embedded in his skull, and it felt warm, pulsing, comforting. Then he discovered the terrible truth. The evil black gem was an eye through which his enemies, the forces of the Dark Empire, could see everything he saw - all the places he travelled, all the people he encountered. And if he refused to carry out their plan to overcome Granbretan, the black jewel could be made to come alive.

And eat Dorian Hawkmoon's Brain.