The shield is a masterwork made of mithril. It absorbs the power of deflected attacks within its metal, transmuting their powers into elemental forces which can then be rebounded back at the attacker under the command of the shields holder. As a magically enchanted masterwork of mithril, it cannot be penetrated or dented by any known weapon except that which is forged of a stronger magic than it's own. Given the strength and power of the magic which created it, the match has not yet been found to break it, especially as those forces not rebounded back to the attacker only serve to strengthen the shield itself.