If you own a set of cards in the Cardverse, you are considered the most powerful and dangerous person everywhere.
Owning a set of cards is very, very, very, very rare. Like nobody knows they basically exist. If you have a set of cards and know how to play with them (Play card games of different sorts); it basically labels you as somebody who knows how to wield/play the royals and the rest of the deck to your will.
If you are found or caught with a set of cards, (as well if you are playing a card game); you are instantly brought to the royalties of your kingdom (or all four kingdoms) and are determined what to do with you.
Ranging from imprisonment to execution.
So play your cards right.
(PUNS!!! :D)