Weapon Expertise is a mechanic unique to Barbarians in Diablo IV, and ties into their ability to equip up to four different weapons at once.
At level 5, they gain access to Weapon Expertise, which can be viewed in the Expertise tab. Every weapon type has a Technique, which goes into effect whenever the Barbarian uses that specific weapon. Every Technique starts at Rank 0, and can be raised up to Rank 10 simply by using the weapon in battle. At Rank 10, these Techniques will gain an additional bonus.
At level 15, you will unlock the quest Barbarian: Masters of Battle. Completing this quest will unlock the Weapon Technique slot.
List of Weapon Techniques
|Weapon||Technique (at Rank 10)||Rank 10 Additional Bonus|
|1-Handed Axe||5.0% increased Critical Strike Chance against injured enemies. Double this amount when using two Axes.||Lucky Hit: Critical Strikes have up to a 55% chance to grant 6% increased Attack Speed for 2 seconds. Double the Attack Speed bonus when using two Axes.|
|1-Handed Mace||10% increased damage to Stunned enemies. Doubles the effect when using two Maces.||Lucky Hit: Up to a 10% chance to gain Berserking for 1.50 seconds when you hit a Stunned enemy. Double this chance when using two Maces.|
|1-Handed Sword||Lucky Hit: Up to a 10% chance to gain 5 Fury when hitting a Crowd Controlled enemy. Double this chance when using two Swords.||Killing a Crowd Controlled enemy grants 15% increased Attack Speed for 3 seconds. The increase is doubled if using two Swords.|
|2-Handed Axe||15.0% increased damage to Vulnerable enemies.||10% increased Critical Strike Chance against Vulnerable enemies.|
|Polearm||10% increased Lucky Hit Chance.||You deal 10% increased damage while Healthy.|
|2-Handed Sword||20% of direct damage you deal is inflicted as Bleeding damage over 5 seconds.||You deal 30% increased Bleeding damage for 5 seconds after killing an enemy.|
|2-Handed Mace||Lucky Hit: Up to a 10% chance to gain 2 Fury when hitting an enemy. The Fury gain is doubled while Berserking.||You deal 15% increased Critical Strike Damage to Stunned and Vulnerable enemies while Berserking.|