Cardist

No mere gambler, this is an arcane caster who has learned to let the cards send magic through him. While others have learned the game and can augment their magic using Decks, the Cardist has an amount of control of the cards. The Deck respects the wielder to heed their requests.
It is no small task to gain the respect needed to influence the Decks and requires years of demonstrating skill and power. Card Magic is considered all pure showmanship by most arcane users. So few have truly earned the title Cardist that it reflect poorly on all who cast magic in this way.
The individual cards have only just awakened, and mostly through adventurers with more guts than sense. Not the types generally associated with studying the arcane. So advancing the art of Cardistry has been slow and full of charlatan looking to make a quick copper piece by selling their useless "techniques."
Through time, the vocation will gain more respect but for now it remains the domain of seedly bard where those desperate enough to make pacts with demons for a greater understanding of the Decks. To begin the journey of being a Cardist first you'll need enough luck to find at least three cards belonging to a Deck. Then dedication to understand the cards. Finally, enough luck to win when you begin gambling. Many prospective Cardists make deals with cosmic or demonic entities to cheat a few of the requred steps.
As you gain more experience gambling and using your cards you powers will grow. To gain the title Cardist you will need to complete one whole Deck, though the definition of a whole deck is often ambigious. A few Decks have been experienced conventionally by adventurers, such as the the Deck of Many Things, and so the whole decklist is thought to be understood. Though there is no requirement that every Deck of Many Things contains the same number of cards. Each could be different with it's own goals and motivations once it has been fully assembled once again.