One for the Morning Glory — John Barnes

The Tale began when young Prince Amatus secretly sipped the forbidden 1 Wine of the Gods, leaving him half the lad he'd once been--literally--for his left side suddenly vanished without a trace!

But, as is often the case in Tales of this sort, the young Prince's misfortune was also a sort of blessing in disguise. For a year and a day later, four Mysterious Strangers appeared, and, as Amatus grew to manhood, they guided him on a perilous quest to discover his true destiny--not .to mention adventure, danger, tragedy, triumph, and true love.