Bronze Demon Cards

The cards are with you, and when they break, you die. Lu Chen has only three bad cards left: Seven of Clubs, Three of Diamonds, and Two of Spades. If he can't form a pair within twenty days, his existence will be directly erased by the system. He tried burning, tearing, and burying them, but the next day the cards returned to his pocket untouched. Outside the east wall, three thugs crept over with spiked clubs. The blade broke, his shoulder shattered, and he slapped the Seven of Clubs onto his chest—three seconds of body hardening, once per day. Three seconds is enough to kill a man. But will the Seven of Clubs come back tomorrow? Can the Three of Diamonds and Two of Spades form a straight? He doesn't know how many rules the system hasn't written out. All he knows is the pain in his left shoulder is real, the cards are real, and the countdown decreases by one each day. This world makes no sense, but it plays by the rules of cards. If you can't complete your hand, you're out. — Description from novelcodex.org