The Dark Soul Stone in Hearthstone is an artifact. After using it, you will get a Diablo's Treasure card and shuffle the card into the deck. Treasure cards are special cards with powerful effects that can provide players with strategic advantages. After using the Dark Soul Stone, players can use Diavolo's treasure cards to enhance their strength in the game.

The above information is for reference only. The specific effects may change due to game version updates. It is recommended to check the game's official website or consult experienced players to obtain accurate information.