The Soul Stone is unique out of all the Infinity Stones, simply because it requires sacrifice before being presented to the holder. It was watched over by Red Skull on the planet Vormir, revealed in both Avengers: Infinity War and Endgame, which is also the root cause of Gamora and Black Widow's death. However, in early development for the final movie, an original Avenger almost turned into the Soul Stone itself.
During a quarantine watch party for Endgame, directors Anthony and Joe Russo were asked if there was any plan to place the Soul Stone in a different place other than Vormir. To which they revealed that, at one point, they considered making Chris Evans' Captain America the Soul Stone. However, the idea "fell away rather quickly." You can check out their tweet below.
While the directors didn't explain further how this idea would have been incorporated into the narrative, the concept is certainly intriguing. The filmmakers didn't specifically say that Cap will physically turn as the stone, maybe he could somehow be in possession of it. Either way, it is understandable why it fell quickly, considering that it'll be much harder to explain how the Avenger was connected to the stone.
Since Red Skull was once Captain America's enemy, it could serve as some sort of connection for this early idea. But, overall, the Soul Stone's purpose in the final cut could have been the better choice.
What do you think of the early concept of Cap turning into the Soul Stone? Share your thoughts in the comments below!