This card can be used to look at your cards from deck.
It can add a monster from your deck to your hand.
Only monsters with combined attack and defense equivalent to your current Life Points could be added to your hand.
Cards to get from Deck
The best time to use Card of the Soul is at the beginning of the duel, since your Life Points at this stage is most constant. The following cards have a sum of their attack and defense that is equivalent to your Life Points: