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From Diablo 4 Wiki

Diablo 4 was announced with five classes and all five have been been revealed. The Diablo 4 classes announced include the Barbarian, Sorceress, Druid, Rogue, and finally Necromancer.

These first three classes were announced at BlizzCon 2019. The fourth class, the Rogue, was announced at BlizzConline in February 2021. The Necromancer was revealed during the Microsoft showcase in June 2022.

All of these five classes have already appeared in previous games in the Diablo franchise. The Barbarian has appeared in every single Diablo game albeit unofficially in the Diablo Hellfire expansion pack.

There have been fourteen different classes throughout the franchise and speculation is rife about the two remaining Diablo 4 classes.

Diablo Franchise Classes

Diablo 4 Diablo 3 XP Diablo 3 Diablo 2 LoD Diablo 2 Diablo Hellfire Diablo
Barbarian Necromancer Barbarian Assassin Amazon Bard Rogue
Druid Crusader Demon Hunter Druid Barbarian Monk Sorceror
Necromancer Monk Necromancer Barbarian Warrior
Sorceress Witch Doctor Paladin
Rogue Wizard Sorceress

Diablo 4 Classes - Skills and Talents

Character development will be slightly different in Diablo 4 with the additions of a talent tree. Skills are split into six categories for each class, and players can decide which skills to use with the return of the elective mode for skill slots.

Diablo IV will differ from Diablo 3 in that players will now be able to add points to individual skills to increase a skill’s rank but it’s not just about increasing the numbers, additional traits will also unlock as detailed here by Joe Shelly, Lead Game Designer.

So you’ve got your skill system, you’re leveling up, you’re getting skill points, you’re unlocking skills, ranking up skills and those rank-ups aren’t just power, they’re not just number increases they can also unlock additional traits for those skills.

If you look at the Barbarian’s Rallying Cry. Rallying Cry grants “Unstoppable” which breaks you out of crowd control (CC) and grants you Immunity. Super helpful if you’ve got frozen in PvP.

But that’s the sort of thing that might not be on the skill initially but as you rank up that skill you would be building toward unlocking that trait. ~ 3 November 2019

Skills will be assigned to left and right mouse button, the left being for the resource generator and the right for the resource spender, and then 1 to 4 for specialised skills.

Skill points can not be reset when allocated the talents can be respecced providing buffs to players and this makes builds more diverse than Diablo 3.

The four revealed classes build on their previous iterations with some skills returning from previous games. Details on skills and talents can be found in the PureDiablo class sections.

Primary Stats

Players will be able to assign Primary Stats to each of their characters as they progress.

Diablo 4 Classes

Diablo 4 Classes Variations
Barbarian character variations.

Customisation

Players will have more customisation options in Diablo 4 including the ability to select a different facial look, scars, skin tone, and more. This is a step up from previous games where all characters started the game with the same appearance and gear being the only differentiating factor between characters in-game. More customisation details are expected to be will be revealed in the future.