Scarlet Witch was by far Marvel’s Phase 4 most powerful character, yet Wanda could not beat Thanos in either Avengers: Infinity War or Avengers: Endgame. Years before Marvel Studios could use the X-Men, Captain America: The Winter Soldier introduced Wanda and Pietro Maximoff, who in this version could not be described as mutants. As a result, a lot about Scarlet Witch and Quicksilver was changed for the MCU, including how Wanda's powers work.

Instead of a mutant, or even an Inhuman, who could manipulate probabilities to control reality itself, Avengers: Age of Ultron’s Wanda was an “enhanced” individual. Scarlet Witch’s powers were originally said to come from the Mind Stone as a result of a series of HYDRA experiments. Wanda was extremely powerful from the start, but before Phase 4 retconned her as the Scarlet Witch, she failed to beat Thanos.

Why Scarlet Witch Failed To Beat Thanos In Infinity War

While Wanda was already one of the strongest MCU characters during Marvel’s Phase 3, she had yet to become the all-powerful Scarlet Witch from Phase 4. It was only in WandaVision that Marvel really began to explore how powerful Wanda Maximoff – now the Scarlet Witch – could be based on the comics. Phase 3 Wanda was essentially an energy-based character whose signature abilities were not that different from other Marvel characters like Jean Grey or the MCU’s Vision. Both Age of Ultron and Captain America: Civil War “nerfed” Wanda compared to the comics, and it was only in Infinity War that Marvel hinted at Scarlet Witch's immense power.

Wanda could not defeat Thanos, but she was able to stop the Mad Titan with one hand while destroying an Infinity Stone with the other. What Wanda did in Infinity War is even more impressive considering that Thanos had five of the six Infinity Stones in his gauntlet. Essentially, Infinity War’s Wanda handled the power of all six Infinity Stones. Infinity War did not include a proper battle between Scarlet Witch and Thanos, as the Mad Titan accomplished his goal when he removed the Mind Stone from Vision’s head. Still, in a fight between Phase 3 Wanda and Thanos with the Infinity Stones, Thanos would likely win.

Scarlet Witch Wasn't At Full Power Until She Learned From The Darkhold

Both Infinity War and Endgame hinted at how powerful Wanda was and could still be. However, neither of those films, as well as none of Wanda’s previous MCU appearances, had come close to showcasing Scarlet Witch’s true power. Fortunately, Phase 4’s WandaVision retconned Wanda’s abilities in the MCU and incorporated the magic aspect of the character. Although WandaVision did not make Wanda into a mutant, it brought the Scarlet Witch alias into the MCU’s canon and made it the name of an entity rather than a title. The reveal that the Mind Stone only activated Wanda’s magic power, plus the introduction of the Darkhold, completely reinvented the character.

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By remembering the true nature of her powers and accessing the Darkhold during a time of grief, MCU Wanda finally became as strong as Marvel Comics’ Scarlet Witch. Both WandaVision and Doctor Strange in the Multiverse of Madness displayed Scarlet Witch’s reality-warping abilities, which make Wanda one of the most powerful beings in the entire MCU. It is safe to say that Phase 4 Scarlet Witch would have defeated Thanos, even if the Infinity Stones were involved. Generally, Scarlet Witch’s powers are only limited by what the story requires. Therefore, if Scarlet Witch returns to the MCU, Wanda could be even more powerful than in her last appearance.

Scarlet Witch Almost Beat Thanos In Endgame

Monica Rambeau pointed out in WandaVision that Wanda could have beaten Thanos in Avengers: Endgame’s Battle of Earth had Thanos not “initiated a blitz.” Thanos had to sacrifice a significant portion of his army to stop Wanda from almost killing him in Endgame. This moment in Endgame, combined with Infinity War’s ending, confirms that Scarlet Witch was already strong enough to defeat Thanos without his gauntlet even before the Darkhold. However, by the end of Avengers: Endgame, it was still unclear which Avenger was the strongest – Wanda, Captain Marvel, or Thor.

Ironically, the most powerful version of Scarlet Witch is technically not an Avenger, not after what happened in Doctor Strange in the Multiverse of Madness. The MCU took six years to showcase Scarlet Witch’s true abilities, but not giving Wanda her full powers during the Infinity Saga was the correct decision after all. Thanos and the Infinity Stones were supposed to be the definitive force of the Infinity Saga, and adding the reality-warping Scarlet Witch into the story would have made things more complicated. In other words, Phase 4 Scarlet Witch would have briefly solved Avengers: Infinity War’s conflict in seconds, which shows how much the MCU's power levels have changed since Avengers: Endgame.