The Forever King (Forever King Trilogy)

The Forever King (Forever King Trilogy) by Murphy, Warren. mass_market edition. ISBN: 9780812517163.

In a darkened house not far from the place where Camelot may once have stood, a madman schemes, plotting toward the day when he will wrest the cup that men call the Holy Grail from the boy who is its guardian. Arthur Blessing is no ordinary ten-year-old. The Grail is his by chance, this time, but the power to keep it--a power as ancient as time itself--is his by right. Now he must stay alive--battling foul sorcery and indefatigable assassins--long enough to use that power. "A fresh and exciting view of the Arthur legend." ―Robert Jordan on Molly Cochrans The Forever King