Every time a creature attacks you, they gain "veil", and therefore attack their owner 50% of the time. Since they keep getting "veil" every time they attack you, (2 turns worth) and they will most likely attack you half of the time... you basically will keep the "veil" on all enemies. This is totally Overpowered. Its crazy. It means you basically just need this one shield... and no creatures... and win against an enemy with any amount of creatures. They do more damage to themselves, than they do to you, since you even get 2 point damage reduction.
half of the time they attack themselves, half of the time they attack you, you get damage reduction, the enemy doesn't. One card.... totally owns any amount of enemy creatures. Now that is overpowered.