Dataminers have seemingly discovered that the first major expansion release for Diablo 4 will likely revolve around Mephisto. According to the dataminers, the expansion is set to be called Lord of Hatred.
According to dataminer YbuBaKa (via ResetEra user Strakt), Diablo 4: Lord of Hatred will include quite a bit of new content, including a new class dubbed the Spiritborn, the return of the Kurast region from Diablo 2, a new Mercenary system, the addition of Runestones, and possibly even raids.
Aside from the addition of raids, most of the potential new features of the theorised expansion seem to revolve largely around Diablo 2, which was the last time the Lord of Hatred, Mephisto, was fought by players. The Mercenary system is also a throwback to Diablo 2, especially since Mercenaries will apparently have their own equipment system and talent tree.
The Spiritborn class has a few mentions in the game’s files, including themes of nature, as well as the idea that the class might have wings, and could even potentially fly.
Diablo 4 is currently in the midst of its second major season, dubbed the Season of Blood. The season brings with it host of new vampire-themed powers. The game was also recently released on Steam, featuring full support for the Steam Deck.