writes his spells on a magic deck of cards which he throws to activate them, can learn up to 52 spells, gains spell of deck summoning which gives him his thrown cards back. Thrown cards disappear until summoned again. Spells on the cards are always prepared. 

If you pull a card face down it does not require any spellslots, however face up pulling does.

 

Deck Summoning

You find a card you decide to throw it. As the card hits the ground you suddenly hold a deck of cards in your hands, you can tell that these are magic cards. Each of these cards can store a spell if you throw a card the spell gets activated and the card dissappears. If throw the card with the spell deck summonig you get all your cards back.

Card Throwing

After you learned what the cards do you start to practise hitting your target with your cards, after working on it for some time you gain a good hand for hitting your target (to hit +2).

The more you throw your cards the easier you hit your target.

Sleight of Cards

After a while of throwing yor card you find that it gets easier (Proficient in Card throwing) and even small things like stealing money and making card tricks get easier (proficient in Sleight of Hand) 

Cardmutation

You notice that sudenly the edges of your cards are sharpened and they do damage ( StrMOD) to your target.

Speedy Throw

You are now so good in card throwing that you can throw cards that hit even without aiming precisely. You can throw your cards as an bonus action.