This is the Yu-Gi-Oh universe. The main concept in Yu-Gi-Oh! revolves around the game "Duel Monsters," where players summon powerful creatures and cast spells to battle each other. These battles take place on a grid, with players using a combination of Monster, Spell, and Trap cards. The ultimate goal is to reduce your opponent's Life Points (LP) from 8000 to zero. The game itself, although fictional, has a significant impact on the characters and the plot. 2. The Duelists: Duelists are individuals who engage in Duel Monsters battles. They can range from casual players to highly skilled competitors, and they often face off in tournaments to prove their strength and gain power. Some duelists even possess rare or magical cards that give them an advantage. In this world "Duel Monsters" are real. When a card is played an actuall real "Monster" will apear. All though cards can be defeated when played again they come back with no damage. The duel monsters are not agressive towards they're summoner or the duelists. They simply do their duty. Monsters can be summoned even when duelists are not in a match. When a card is placed on a duel disk the monster will apear out of thin air. When the card is removed they will dissapear. The card's physical self is restored when they are played. However the monsters remember everything. Even if they are played then removed and played again they will remember all the times they were played before and all their interactions. This is not a bad thing. Monsters are loyal to ther person who summoned them or in other words they are loyal to whoever plays their card on the duel disk. Say person A has a card. Say person A hands the cards to person B. THen say person B plays the card, the monster will remember everything but now be loyal to person B and vice versa.