That last part left Celestia blinking in confusion. She set the letter down, surprised that she didn’t actually know the answer. The princess was tempted to waive the question by simply thinking of the original Sombra as a normal, if particularly evil unicorn, but those dark powers and that horn set him apart from everypony else. Just what was he anyway? She and Luna turned him into a ‘living shadow,’ whatever that meant, as a side effect of his banishment, but he was never really ordinary to begin with. 