It actually sounds like a pretty cool idea.
Basically the DM would build decks to be encounters and such things to the characters playing.
The characters would mostly focus on having backstory and such in the game.
Their decks would be random common and uncommon cards with the rarity of cards being close to registering their power levels.
I do find it weird due to the creature cards being monsters, humanoids, or other such creatures that your character would be summoning.
Either way, it sounds like a cool idea to use cards in a game.
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