Hi the power of your collection determines what league you can play in.
Each card has a DEC burn value and adds to your overall power.
You can find the power of a crad in game by clicking at the card the number on the very right stating DEC is the power of the card.
This chart shows all burn values of all cards :)
!PIZZA
$PIZZA@tscott! I sent you a slice of on behalf of @solymi.
Did you know Pizzabot speaks Spanish if you use the command ESPIZZA? (1/10)