Diablo 4 gives players access to five unique classes. Each class will prioritize different weapons in combat and have its own skill trees, along with an additional bonus mechanic to further let players customize how their play their character.
For the Barbarian, players will earn weapon expertise the more they use a specific weapon in combat. Right away, you can level up each weapon's expertise level, but you won't be able to take advantage of the bonuses provided by the levels until you complete the Barbarian-specific mission.
Complete Barbarian: Masters Of Battle Quest
Upon arriving at Ked Baru and reaching level 15 as a Barbarian, you'll get a marker on the blacksmith indicating that they have a quest for you. The Blacksmith will tell you of another nearby Barbarian who would be willing to let you into their clan as long as you pass the test. Go out of the town to find Katra, who will mark the hunting grounds on your map.
To complete this quest, you'll need to first kill 30 bandits and 30 beasts within the hunting grounds. This is a fairly simple task, as enemies will scale to your level. Bandits are found more around the edges of the hunting grounds, with beasts being found towards the middle. There is no specification on what kind of beasts or bandits need to be defeated, letting you ignore tougher ones should you wish. There is also a shrine near the center of the hunting ground that can be used to help you eliminate the required enemies. Katra will also be fighting with you, giving you a bit of help when needed.
Upon finishing off the enemies, you'll be led to a cave where a much larger beast must be faced in a small cave. This beast will charge around the cave, making dodging out of the way important. It also comes with the bonus Shadowed ability, summoning a second shadow beast to attack your current location. Once the shadow beast is spawned, reposition on the other side of the main beast and out of range of the shadow beast, as it won't be able to follow you around. Defeat this beast and return its head to Katra, then turn in at the blacksmith to complete this quest.
Using Weapon Expertise
Weapon Expertise is a unique Barbarian mechanic that rewards players for using a specific weapon more often. In the expertise menu, you can see your progression for each weapon type, along with all the available weapon types you can level up. You can gain expertise on a weapon simply by fighting with it. After reaching specific levels of expertise with a weapon type, you'll gain a bonus with that weapon type. While a weapon, its corresponding weapon expertise will be in effect. After completing the Barbarian: Masters Of Battle quest, you'll be able to equip a second expertise that will always be in effect, no matter what weapon you are using.