Shield blocks 20% of MELEE attacks made against u
A character with no shield masteries succeeds in shield defense about 50% of the time against ARCHERS
A character with Shield Mastery 2 such as a lvl 28+ paladin, succeeds in shield defense against an ARCHER about 75% of the time
A character with shield mastery 4, available at lvl 52, succeeds in shield defense 99% of the time, the catch is, you MUST BE FACING THE ARCHER, if you turn around .. ur toast
usual shield defence = damage you normally get divided by 2
there is a 5% chance that your shield can block the whole attack, and you only get 1 damage on you.
When shield defence suceeds .. the game tells you "Shield defense has succeeded.". When that 5% chance works... the message is "Your excellent shield defense has succeeded!"