Diablo 4's Barbarian can be tricky to level, with most builds requiring endgame talents and skills to become fully optimal. The Whirlwind build is not only the strongest choice once maxed out, but it also gives Barbarian the best chance at quickly leveling up to max. Focusing on dishing out constant AoE damage while maintaining a variety of powerful buffs, Whirlwind Barbarian is easy to play and fun to progress with.