Diablo 4 offers players many ways to power up their characters. While general farming and looting will level you up and have you getting new gear, increasing your World Tier will have you receive better rewards and XP but give you more of a challenge to earn it all.
Diablo 4: World Tiers Explained
World Tiers affects both the difficulty of the game and the rewards players get in Diablo 4. Here is how they work.