Free Duel lets you challenge any of the 39 campaign duelists from Yu-Gi-Oh! Forbidden Memories, plus a fully customizable AI opponent, all with configurable settings. The page is your pre-duel lobby — select an opponent, configure your deck and game settings, then start the duel.

The workflow is simple: pick an opponent from the duelist grid below → select which card groups form your deck using the Deck Settings panel → adjust Life Points, deck size, and field options in the Duel Game Settings → click your chosen opponent to begin the duel.

Your deck is built from the card groups you select in the Deck Settings panel. Each group represents a curated collection of cards organized by type, guardian star, fusion targets, or duelist associations — you can select one or more groups, and the system draws your deck from the combined pool of their cards.

Use the POOL / DECK mode toggle to control how cards are drawn from your selection. POOL mode treats card quantities as probability weights, while DECK mode simulates building a real deck with the game's 3-copy limit (limit x3 option).

You need enough cards in your selected groups to fill your chosen deck size. If you haven't selected enough, the system will show an error when you try to start a duel.

• Life Points (default 8000) — Starting LP for both players. Can be set from 1 to 99,999.
• Cards (default 40) — Your deck size. Minimum 5, maximum 999.
• Opponent Field — Toggle whether the opponent starts with a field spell advantage, matching the original game behavior.

These settings apply globally to all duels started from this page. Adjust them before selecting your opponent.

Clicking a duelist navigates to the duel page at /duel/{duelist-name}, where the actual duel takes place. Before the duel starts, the system validates that your selected card groups contain enough cards to fill your deck.

If your selected groups don't have enough cards, you'll see an error message showing exactly how many cards you have versus how many are needed. Go back to deck or this page to adjust your group selection or deck size.

Once validated, the duel begins with your deck randomly drawn from the combined cards of your selected groups. The opponent uses their own deck and AI behavior from the original game.

The purple icon at the end of the duelist grid represents a fully customizable AI opponent. Clicking it opens the Custom Duel Configuration page.

You can customize the opponent's deck composition, AI behavior parameters, field spell advantage, and even the card drops they reward. This is useful for testing specific strategies, practicing against tailored scenarios, or creating custom challenges.

When you click a duelist without enough cards selected to fill your deck, the system shows an error. This happens because your selected card groups must contain enough total cards to meet your configured deck size.

In DECK mode with limit x3 enabled, each unique card can contribute at most 3 copies. In POOL mode, you need enough unique cards multiplied by 3 to fill the deck. The error message shows exactly how many cards you have versus how many are needed.