Avengers: Infinity War - Predicting The Entire Plot In 20 Steps

15. Thanos/Gamora's Back-Story Is Revealed (Plus Soul Stone Hints)

When Thor reveals that Thanos is on the trail of the Infinity Stones, it will spark something in Gamora to explain exactly why that's going to be a bad thing. Up to this point, nobody really knows why Thanos wants them - other than as a means to boost his power - but her explicitly mentioning his desire to wipe out half of existence will set that right.

Expect this to be a fairly substantial flashback exploring the history of Titan and how it over-reached and destroyed itself (partly through over-population) and how that informed Thanos' attempts to rebalance the universe. Hopefully, through establishing Gamora's story, we might find out why Thanos wants to "adopt" his own children since it seems so strangely alien to the make-up of traditional supervillains.

One theory suggests that Thanos was breeding his "children" as hosts for the Aether to unlock the Reality Gem - or as the key to unlocking the Soul Stone (perhaps hinting that it requires a sacrifice of "love" to be revealed?), which would definitely be an interesting direction. And it would definitely explain why Thanos chose to wipe out all of Gamora's race but not her - if it was a means to begin rebalancing the universe, keeping her alive would be redundant.