I’m not really sure what to make of the Soul Stones in the Diablo ‘verse. I’ll admit, I’m going on old knowledge, and it isn’t like there are other examples of such things. I suppose I’m just curious about how they work, and what’s implied by the way they function. I previously gave a summary of their appearance in three of the Diablo games: Diablo, Diablo 2, and Lord of Destruction.

In the background for the games, the Soul Stones were used by some powerful mages to bind the Three Prime Evils some time after they invaded the Natural world. Throughout the games, we get hints that the Prime Evils (Diablo, Mephisto, and Baal, the Lords of Terror, Hatred, and Destruction, respectively) engineered their exile from the Hells so they could put in some far-reaching plan to take over the world of Sanctuary, which is where most of the action of the games takes place.

In the climax of Lord of Destruction, we get a glimpse of the World Stone, which I’m going to assume was the source of the Soul Stones used to trap the Three Prime Evils. Baal is in the process of corrupting the World Stone for some reason, I don’t think it’s ever made clear. Having already defeated his “brothers,” Diablo and Mephisto, and shattered their respective Soul Stones (which I guess banishes them back to Hell? I don’t know) Baal puts up a bit of a fight, but he goes down as well.

We see that, through the stones, the Prime Evils are able to exercise their corrupting influence: Mephisto corrupts the priesthood in the city of Kurast, and Diablo possesses the body of the hero from Diablo. For some reason, after his defeat at the hands of the player, Mephisto is unable to affect any real damage up until the destruction of his Soul Stone in the second quest of Act 4. Why? He got a whole priesthood before! And Diablo got the hero from the first game! What was different this time?