Concerns Over Ultron's MCU Return
The Marvel Cinematic Universe (MCU) is known for its interconnectedness, with major characters making unexpected appearances in various movies.
This interconnectivity is not limited to heroes, as villains like Samuel Sterns have also made surprise returns, such as in Captain America: Brave New World, 17 years after his last appearance.
Another notable example is Tom Hiddleston's Loki, who has appeared multiple times throughout the franchise.
The studio made this clear when Robert Downey Jr. appeared unannounced in The Incredible Hulk
Author's summary: Ultron's return may ruin the Avengers villain.