Ok here is the question...

P.A. uses "Diamond Vision" and gets Pot of avarice w/ the effect...During the next turn when the player decides to use the effect of POA, does he have to bring back 5 monsters to the deck? or does the player just draw 2 cards??

Thanks in advance

This is Diamond Dude's effect:

You activate its effect which means you still return 5 monsters from your graveyard to your deck and then draw 2 cards.But,you can't activate it if you do not have 5 monsters in your graveyard.