The Harbinger of Hatred is back in Diablo 4 Season 10, and taking him down has been one of the most intense parts of the new content. Getting to him isn't as simple as walking into a dungeon—you need to farm three Abhorrent Hearts from Urivar first, then make your way to the Harbinger's Den west of Kurast in Nahantu. Once inside, the altar lets you use those hearts to summon the boss...