The Yu-Gi-Oh! anime, in which serious disputes are resolved with a children’s card game, is known for its share of dramatics and exaggerations. But more importantly, it’s also known for its hilarious tendency to break its own rules and create situations that would realistically never happen in the real-life trading card game. The best example of this lies in its protagonist Yugi Muto and his nearly unwavering ability to win any duel, no matter the odds. While his own plot armor has a lot to do with this, he certainly seems to have lots of powerful cards at his disposal. Let’s take a look at his own deck and determine just how likely victory would be for Yugi if he wasn’t a shonen anime protagonist.
To start, consider one of his most iconic monsters: Exodia. While the cards didn’t stay in his deck for very long after Weevil stole and tossed them into the ocean, the Forbidden One still helped Yugi defeat Kaiba in what remains one of the most memorable moments in the anime to this day. But as for real-life applications, the effectiveness of Exodia in Yugi’s deck leaves much to be desired.
While Exodia decks have seen some prevalence in the past, in a world without ban lists its actually the strongest deck in the game. It’s not the Exodia cards alone that make it so powerful, though. Generally, for an Exodia win condition to pan out consistently, an entire engine needs to be built around getting those five cards in the players' hand as soon as possible. These types of decks involve three copies of each piece of Exodia and a large majority of the deck being filled with draw and mill spells that clear through the entire 40 cards as soon as possible. Not only does Yugi’s deck lack those resources but it also actively ignores the potential to bring Exodia out quickly with countless unrelated monsters and spells.
On the topic of those unrelated monsters, among them is Yugi’s ace: Dark Magician. It's by far the card that received the most playtime from Yugi and a constantly recurring card in most iterations of his deck. While it has a respectable attack stat, it’s a normal monster with no extra effects. This doesn’t stop the anime from getting creative and giving Dark Magician all kinds of unique interactions with cards that either grant it special abilities or boost its attack power by some ridiculous degree; but, none of these would help Yugi in an actual match.
When it comes down to it, Dark Magician runs into the same problems as Exodia. The card isn’t inherently bad but just lacks any kind of real support to enable it in Yugi’s deck. The real cards in Yugi’s possession don’t do much to help his case either, as most of them simply offer minor boosts to the Spellcaster’s attack. Dark Magician Girl is a bit better off, since she has potential to grow stronger than a single Dark Magician with enough in the graveyard, but Yugi almost always gets Dark Magician back on the field as soon as he can, which renders her pretty useless.
Finally, we have Yugi’s last big monster, Slifer the Sky Dragon. Out of all aspects of his deck, this is by far the one with the most potential. With his technique of summoning Queen’s Knight and special summoning King’s Knight along with Jack’s Knight, he at least has an engine to produce the three tributes required for the Egyptian God card. There’s just one problem. For Yugi’s game plan to work as intended, he needs to summon these three monsters and wait until his next turn to bring in Slifer. During this turn, anything from spells to remove monsters or even a monster that can beat Queen’s Knight (who isn’t particularly strong) would quickly poke a hole in his strategy.
At the end of the day, Yugi’s greatest enemy isn’t his opponents but his lack of deck-building knowledge. If he were to face the far more consistent decks that exist in actual an Yu-Gi-Oh! match, his defeat would be almost certain.