An important aspect to keep in mind of The Card Knight is to
flesh out how they came to be in this situation. Who drew
you? If so, what orders have they given you? Are they even
alive? If not, what do you do now with your freedom? Where
or when do you originally come from? Did you exist at all
prior to being pulled? How long have you been in servitude?
Or perhaps your Knight has nothing to do with the DoMT.
Perhaps you found a similar magical artifact which has
latched onto you as a curse, or you are simply a practitioner
of wild chance-based magic, maybe you use tarot cards to
read the future which also give you power. You can flavor the
Card Knight's relationship with his Deck of Chivalrous Duty
in any way you please.

Bonus Proficiency

Starting at 3rd level, you gain proficiency in playing cards,
the Dexterity (Sleight of Hand), and Charisma (Deception)
checks. Your proficiency bonus is doubled for any ability check you made when dealing with your playing cards.

Deck of Chivalrous Duty

At 3rd level a deck of 20 cards manifests itself into your
equipment. This deck is magically tethered to you. If the deck
is moved farther than 5 feet away from your position, it will
instantly teleport back into your possession. As a bonus
action you may draw a random card from this deck which will
then produce a magical effect. You may have this effect take
place immediately after drawing or you may store the card
and its effect for later. You may then activate a stored card as
a bonus action. Unused stored cards are lost after
completing a long rest. Once the card's magical effect is
activated, it vanishes, and is shuffled back into the deck. You
may only draw 3 cards from the deck per long rest. Any
cards drawn exceeding that limit will appear to depict a
Jester in black and have no effect. Additionally, if anyone
other than you pulls a card, the card will depict a Jester in
black and have no effect. Effects which require a saving
throw have a DC equal to 8 + your proficiency bonus + your
Charisma modifier. The possible cards and their
corresponding magical effects are at the end of this
document.

Hit Me

Starting at 7th level, once per long rest, you can return a card
back into the deck, shuffle, then draw again. This can be
done immediately after drawing a card or as a bonus action
with one of your stored cards. This draw does not count
against your three draws per long rest.

All In

At 10th level when performing an Action Surge, you can
simultaneously draw a card from the deck. This draw does
not count against your three draws per long rest, and the
card's effects are activated immediately.

Pocket Aces

At 15th level, you can decide to keep up to two of your drawn
cards indefinitely. These cards become your Pocket Aces
and do not return to the deck upon completing a long rest.
These cards also do not count against your three draws in
subsequent days. You may only have up to two Pocket Aces
at a time. Upon activating one of your Pocket Aces it vanishes
back into the deck.

Wild Card

At 18th level, you gain access to a card depicting a Jester in
red. This card can be treated as any of the other cards, and
you can activate its effect as a bonus action. The card will
then vanish, but returns after a completed long rest.