Apr 1, 2016, 15:4504/01/16
Total # of rewards are 4. You get chests as per your acheivement.
Let say for raiding event
1st reward is 75K, 2nd is 500K, 3rd is 2500K and last one is 7500K.
If you raided 0-75K you get none
if you raided 75-500K you get 1st chest
if you raided 500K-2500K you get 2nd chest
If you raided 2500K-7500K you get 3rd chest
If you raided +7500K you get 4rth.