Sacred Haven of Debauchery

No, the only similarity to Diablo is the top-down perspective. Otherwise, this game is completely different. If Diablo is just mindless hack-and-slash, then this game has many quests, dialogues, puzzles, and traps, and you can also pick locks and steal. The character progression is different, there are many skills, including those that depend on the character's profession, etc.

Added after 3 minutes
And there's a lot more! In my opinion, this is the best fantasy world.