First, I want to point out the description is wrong. This game, alternatively known as "Duel Masters: Cobalt", is about five young duelists (Rusty, Luc, Rebecca, Flynn, and Trey) handpicked by notable anime character, Knight, to partake in the Five-Colors Tournament and stop the evil Widow and her gang from stealing brand new cards. It is a lot more awesome than it sounds, as the method of making new cards in the game is through a ritual that connects the human world and the creature world, creating a portal that links new creatures on to brand new cards.
Second, as for my greatest memory- where do I begin? Literally one of my favorite PS2 games of all time. I remember getting it and feeling surprised by the amount of original characters in the game with only two being from the anime, and one of them is a secret character you have to unlock in the arcade mode by winning 100 duels. My top 3 characters within this game will always be Trey, Luc, and Flynn due their deep story narratives on inferiority, being framed for cheating, and straight up covert events. I have always wanted either a remake or an updated rerelease with more cards, as the card pool for this game is incredibly limited but makes up for it with some of the best creature animations you have ever seen on the PS2. I don't think there is anything on the PS3, PS4, or any of the other consoles that hold a candle to how awesome this game looks. And this was all done by an American team, no Japanese developers involved, yet incorporates some incredible anime-style character designs that you just can't get anywhere else. Arguably, it is even better than the other Duel Masters games over on the Gameboy Advanced. Seriously, I would buy this game on my Switch if I had the chance.