For Dead Eyes Only by Dean Wesley Smith

Lo Wang: The Shadow Warrior. The darkness made whole, the night made flesh. Master of all martial arts. Master of all explosive weapons. The Shadow Warrior fights neither for good nor evil but for himself alone, bent on finding those who betrayed him and bringing them to his own personal brand of bloody justice. But first they must be found.

When a mysterious stranger offers Lo Wang the location of his worst enemy in return for a small favor, Lo Wang agrees. Soon he finds that far more than his vengeance is at stake. A deadly device has been stolen from the United States government, a device that an evil man can use to remake Earth in his own image at the price of untold death and destruction.

Lo Wang must destroy the device before time runs out on both his vengeance and the lives of billions. To do that he must battle forces that match his own almost unlimited powers, determine whom he can and cannot trust, and uncover secrets meant...For Dead Eyes Only.