Here's why:
* Forbidden Memories' Card Pool: The game features a limited card pool compared to the modern Yu-Gi-Oh! TCG. It doesn't include cards like Dark Magician that were introduced later.
* Limited Duelist Choices: The game has a set roster of duelists, each with their own specific decks. Dark Magician isn't included in any of these decks.
* No Trading System: There's no way to trade cards or obtain them through any other means outside of what the game provides.
So, even though Dark Magician is a powerful and iconic card, it's not available in Yu-Gi-Oh Forbidden Memories.
If you're looking to play with Dark Magician, you'd have to explore other games or versions of the Yu-Gi-Oh! TCG.