The dices purpose

See the dices are all about luck you use the to show what you would like to do
example if the opponent Gravios will use a Gravios Beam he or she will have to roll an instant death attack dice if he rolls 7 up to 12 you will get hit by it and die but you can roll the dice Evade if you can match or go higher than the enemy rolled you avoid it but if you roll lower you are dead

Shield is only for SnS users

Example

Gravios uses Sleep Gas

The member 'mykhel918' has done the following action : Battles

'Sleep Attack' : 10

I have to evade
( You can't shield a Gas attack)

The member 'mykhel918' has done the following action : Battles

'Evade' : 8

Now Mykhel will be asleep for two turns

Gravios uses Gravios Beam
( In this case you don't roll because Mykhel is already sleeping so he can't move)