Phase 4 of the MCU has yet to reveal Cap America’s greatest mystery in Avengers: Endgame, which was released in 2019. A significant amount of damage is done to the shield during Captain America’s one-on-one battle with Thanos. Even with Steve Rogers’ shield and Thor’s hammer, Mjölnir, in hand, Thanos manages to chip away at the vibranium of the star-spangled weapon, nearly breaking it in half.

So when Steve returns to the future, he leaves the shield at home when he returns to the Infinity Stones. A few seconds after leaving, he reappears as an elderly man in the form of an old man. Sam Wilson is given the Captain America shield by Endgame’s older version of Steve, who brings it back with him in perfect condition. The implications of this are explored further in the Disney+ series The Falcon and the Winter Soldier.

Even more puzzling is the fact that the question of how Steve came to acquire this shield remains unexplained. Steve’s return to the past is one of the most puzzling plot points in the franchise, even though the rules for time travel laid out by Avengers: Endgame and subsequent MCU projects such as Loki are often chaotic and largely incoherent. In Endgame, it is established that changing the past does not alter the present or the past of the individual. As a result, if Steve was unable to alter his past self’s course, Captain America’s shield would have taken the same route alongside him, ultimately leading to its destruction.

What Does Peggy Carter And Thanos Have To Do With Cap America Mystery

Steve’s quandary raises a number of questions within the MCU canon. The futures of characters like Peggy Carter in Agent Carter, Captain America: Winter Soldier, and Captain America: Civil War are already established. But, surely, Steve returning to marry her necessitates a major change in her life, which is impossible. On top of all that, Loki sets up an enforcer, the TVA, to stop people like Steve from doing exactly what they do – tampering with the universe’s timeline.

After having the shield at any point between the end of World War II and its final battle with Thanos, there is no point in Avengers: Endgame where old Steve could have taken it that it would not have been missed. It is possible, however, that old Steve somehow acquired his version of the shield from another universe while on his journey to return the Infinity Stones.

Perhaps his journey across the multiverse took him to a timeline where Captain America had either died or retired, making the shield unnecessary. There are many speculations about what might have happened if Steve had gone back in time, but so far Phase 4 of the MCU doesn’t appear to be interested in addressing them.