20 Things You Somehow Missed In Avengers: Infinity War
4. Blood Stains On Vormir
Though half of all living creatures were killed by Thanos at the end of Avengers: Infinity War, there were three deaths that were much more permanent. Sure, all three characters will have appeared again in the MCU by the time Guardians 3 releases, but as different versions of themselves.
Along with the deaths of Loki and Vision, Gamora's demise was much more final. In order to gain the Soul Stone, Thanos had to sacrifice that which he loved, and so without hesitation hurled his favourite daughter over the edge of the cliffs of Vormir to her death at the bottom.
As the shot zooms in on Gamora's body, naturally she takes all the focus, making the blood stains dotted about her easy to miss. So, it would appear that there were people who did know where the Soul Stone was before Thanos, and they tried to procure it from the Red Skull. However, by the time Thanos got to Vormir, the stone was still there.
The most obvious explanation, and it's a dark one, is that a stone seeker sacrificed someone that they didn't truly love. The body still hit the ground at the foot of the cliff, but they could not make the everlasting exchange for the Stone, allowing Thanos to gain it however many years later.