The Prince of the Changed White was the Emperor

'''A boy made emperor, beheaded before becoming a man. Such was the tragedy brought on by the destiny of the first noble mage. “Ian. May you not be born in your next life.” With the traitor’s cruel words, I thought everything was over. I thought so… but… “You are a symbol of peace. What greater glory could there be for one of such lowly birth?” I became the illegitimate son of a marquis family annihilated 100 years ago. Lowly, ignorant, destined to be sold as a hostage to the bordering barbarians.'''