S.T.A.L.K.E.R. 2: Heart of Chornobyl developers have released a short video showcasing the updated Soul artifact. It was also revealed that in the new game, it will boost stamina.
The developers describe the Soul as a popular souvenir from the Zone and a favorite artifact among stalkers due to its properties that make the owner more resilient. According to the developers, despite the artifact's fragile appearance, no one has ever managed to break it. Soul appeared in all the games of the original trilogy. In Shadow of Chernobyl and Clear Sky, it increased the protagonist's health, while in Call of Pripyat this artifact increased the speed of health regeneration. This is what the Soul looks like in previous games of the series: