Soul Stone

The Soul Stone was an incredibly powerful and ancient stone capable of manipulating souls. An Infinity Stone, the only two known individuals to possess it are Thanos and Clint Barton. The Soul Stone is uniquely protected; one cannot obtain it by grabbing it. Instead, the Soul Stone must be obtained by sacrificing that which you love most. The stonekeeper of the Soul Stone is Johann Schmidt, who became the stonekeeper of the Soul Stone after touching the Space Stone

Thanos, as part of the Infinity War, obtained the Soul Stone by sacrificing Gamora. The Soul Stone was ultimately destroyed by Thanos in the wake of the Snap.

In 2023, the Avengers initiated a plan to resurrect the victims of the Snap. Clint Barton and Natasha Romanoff were sent to obtain the Soul Stone, forcing Barton to sacrifice Romanoff in order to obtain the stone.