If you're only familiar with the 4Kids dub of Yu-Gi-Oh!, you've missed out on a lot of gruesome content. Even if you watch the anime with subtitles, you're only getting a small portion of the graphic content the series has to offer. In the manga, things get very disturbing. It's amazing this story was ever marketed to children.
Dark moments from the Yu-Gi-Oh! manga include self-harm, aggression toward others, forced hallucinations, and more. Yu-Gi-Oh! fans with a low tolerance for horror might want to leave this series on the shelf - but those with a penchant for creepy manga might just end up loving it.
Yu-Gi-Oh! isn't the only manga with a far more cheerful anime counterpart, but it's one of the most memorable.
Pegasus meets a gruesome end in the manga. At the conclusion of the Duelist Kingdom arc, Yami Bakura rips Pegasus's Millennium Eye out, instantly putting an end to his life.
Pegasus reappears several times in the Yu-Gi-Oh! anime and its sequel series, Yu-Gi-Oh! GX and Yu-Gi-Oh! 5D's. In the manga, however, he remains in his grave.
You wouldn't know it from simply watching the Yu-Gi-Oh! anime, but Bandit Keith actually meets his end in the manga. In the anime, Keith threatens Pegasus as a response to his humiliation following his loss to Joey in the Duelist Kingdom tournament. Pegasus opens a trap door and sends Keith plummeting to the rocky sea below - but he somehow survives.
In the manga, there's no trap door. Keith threatens Pegasus, and Pegasus responds by using mind control to force Keith to take himself out. Keith even does the deed with his own hand, which is turned into a side arm.
Dark Yugi torments many people who wrong his kinder personality. When Goro Inogashira wrecks Yugi's Carnival Game booth at the school festival in order to make room for his okonomiyaki grill, Dark Yugi rears his head and ropes Goro into playing ice hockey using frozen explosive chemicals over the grill.
When Goro loses, the chemicals explode in his face, ending him instantly.
There are some hints that Joey's family dynamic at home isn't exactly perfect in the Yu-Gi-Oh! anime, but the manga presents his home life as absolutely devastating. In the manga, Joey's father has problems with both alcohol and gambling. But he isn't the only person to suffer as a result of his alcohol use - his constant drinking causes him to physically lash out against his son.
While we never see him harm Joey, it's implied when he throws a bottle of liquor at Téa, Tristan, and Yugi, who he mistakes for his son.