Guardian Angel — Adrian Howell

Adrian Howell carries a dark secret: one that could save the world from psionic domination. But this secret must be kept even from his allies. As the Angels make their final push to end their 700-year war with the Guardians and set their sights on the rest of humanity, Adrian's small band of freedom fighters must find its way through a maze of betrayal and deceit, and somehow restore the balance of power before it is too late. And yet, as the war approaches its tipping point, the greatest battle Adrian faces now is not one that is fought with psionics, but deep within the confines of his own scarred heart. For even in the unlikely event that Adrian succeeds in his mission, the price of victory might not only be his life, but his very soul...
(Guardian Angel is the fifth and final book of Adrian Howell's PSIONIC Pentalogy)

Read all five books of Adrian Howell's PSIONIC Pentalogy in order:

Book One: Wild-born
Book Two: The Tower
Book Three: Lesser Gods
Book Four: The Quest
Book Five: Guardian Angel