[quote=@Necroes]
[@Guardian Angel Haruki] Voth has proficiency with playing cards. What stat would be rolled to go alongside that proficiency? I could see charisma, but is it more important to have a good poker face, or to be able to read other people's poker face?

Also, Voth has a deck of playing cards. I would like to state for the record now that they are marked in a manner he is familiar with, as he has owned them for a long time, but he himself did not actually put on the cards.
[/quote]

It depends on what Voth wants to do with the playing cards...

If Voth wants to understand the rules of a card game, calculate odds, or spot a cheater, that would be an Intelligence check.

If Voth wants to bluff, intimidate, influence a player, or keep a poker face during a game, that would be a Charisma check.

If Voth wants to cheat in a card game by swapping cards or hiding them, that would be a Dexterity (Sleight of Hand) check.

Marked cards would help Voth with identifying cards and thus identifying if someone is cheating, or if someone is keeping a poker face. 

However, marked cards do count as cheating before a game. So, for having your cards marked, I would like a retroactive Sleight of Hand check with your playing cards proficiency to see how discreet those marks are.