Concerns Over Ultron's MCU Return
The Marvel Cinematic Universe is known for its interconnectivity, with major characters making unexpected appearances in various movies.
This was evident when Robert Downey Jr. appeared in The Incredible Hulk, and also with the recurring appearances of Samuel L. Jackson.
Villains have also made surprise returns, such as Samuel Sterns in Captain America: Brave New World, 17 years after his last appearance, and Tom Hiddleston's Loki, who has appeared multiple times throughout the franchise.
The Marvel Cinematic Universe has always been built around its interconnectivity.
Author's summary: Ultron's return may ruin the Avengers villain.