Diablo 4 features 5 classes from which you can choose, the melee Barbarian; the ranged DPS Sorcerer, the Nimble Rogue, the multipurpose Druid, and the nigh unkillable Necromancer. Each of these classes has its own special class-based mechanics.
Diablo 4: How To Unlock Barbarian Specialization
The Barbarian Specialization in Diablo 4 makes you utilize the Arsenal System; here's how you can unlock it in the game.
