Títulos Alternativos: FR: Forteresse imprenable -Christmas eve- | US: An Impregnable Defense: Christmas Eve | DE: Uneinnehmbare Festung – Christmas Eve | CN: 难以攻破 | JP: 難攻不落-Christmas eve- | TW: 難以攻破-Christmas eve- | MAL: Ookami Shoujo to Kuro Ouji | ALT: Ookami Shoujo to Kuroouji | ALT/EN/MAL: Wolf Girl & Black Prince | JA: オオカミ少女と黒王子 | MAL: Ookami Shoujo to Kuro Ouji: Wolf Girl & Black Prince | MAL: Wolf Girl and Black Prince