Good class combinations will make it faster and easier to conquer Diablo 4. Certain pairs of classes have skills that synergize or otherwise buff each other. If one class gets bonuses on vulnerable targets, why not team them with a class specializing in inflicting the vulnerable status.
Any co-op pair is strong enough to complete the game on normal difficulty. These combos are more for higher difficulties in Diablo 4, like Torment mode. In those, enemies hit much harder and have additional defenses to overcome.
The Necromancer can summon multiple minions, while the Druid has means of buffing allies or hinder foes. This team uses these decoys to remain nearly untouchable. However, this combination will lack some raw power seen in other Diablo 4 pairings.
Necromancer players start with four initial skeleton warriors within the Book of the Dead. At level 15, they can summon mages, and then a golem at level 25 in Diablo 4. To make a highly defensive army, one will want Defenders, Cold, and Iron for each category.
The early Necromancer skills in Diablo 4 mainly serve as perquisites, but Decompose, Unliving Energy, and Hewed Flesh can all be useful later on. To help with summons, players will want to pick up Skeletal Warrior Mastery, Skeletal Mage Mastery, Golem Mastery, Transfusion, and Bond in Essence. Horrid Decrepify, Plague Corpse Explosion, and Blighted Corpse Tendrils are all helpful upgrades as they provide all sorts of debuffs against enemies. For final abilities, the Supreme Army of the Dead should be the selected ultimate and Kalan's Edict as the key passive.
Druids gain bonds with four different animal Spirit Boons. The Deer, Eagle, and Wolf slowly unlock while leveling and grant additional boons with Druidic Spirit Offerings. The final animal, the Snake, needs all four of its boons purchased at once to become accessible. Gift of the Stag, Iron Feather, Calamity, and Calm Before the Storm should be selected for each animal.
When working with a Necromancer, the Druid will want to build around skills that mostly cripple foes rather than outright destroy them. They will spend the most time in human form but will transform into a Werebear occasionally. Early skills should include Wild Wind Shear, Abundance, and Innate Cyclone Armor.
Druid's core skills in Diablo 4 will use Brutal Wolves, Innate Debilitating Roar, Ferocious Poison Creeper, and Natural Hurricane. Further helpful passives include Natural Disaster, Resonance, Quickshift, and Envenom. Prime Petrify is a tremendous ultimate for locking down enemies, and Perfect Storm is the key passive to harm those already hit by debuffs.
Both the Sorcerer and Rogue excel at fighting from afar. This allows the team up to destroy enemies before even being spotted. However, things can get much messier once in an up-close brawl. The Sorcerer has options of escape, while the Rogue is still competent in melee range, even during a PvP match in Diablo 4.
Sorcerers' unique class mechanic is Enchantment. This allows them to buff two of their active skills with new properties. An Enhancement overlaps with upgrades, making a truly unique spell. For teaming up with a rogue, one will want to select Teleport and Blizzard.
In a Sorcerer-Rogue team, the spell caster will mainly want to focus on ice spells to slow down or fully freeze enemies. They will unlock Glitter Ice Bolt as simply a prerequisite spend but will mainly use Destructive Frozen Orb and Mage's Blizzard as their main attacks. Shimmering Teleport and Shimmering Frost Armor will serve as defensive tools.
Specific equipment may have Aspects of Power in Diablo 4 to further strengthen active skills. Remaining skill points will be spent more on helpful passives, like Elemental Dominance, Elemental Attunement, Mana Shield, Cold Front, and Frigid Breeze. Deep Freeze should be selected as the ultimate skill, and Shatter for the key passive.
Rogues have Combos Points as their unique class feature. After hitting one to three times, the next hit will enhance an active skill. This should be used to improve Barrage or Rapid Fire. Starting at level 20, certain enemies will be marked with Inner Sight. Killing them will give the rogue unlimited energy use for a short time.
When partied with a Sorcerer in Diablo 4, the Rogue player will want to invest in bow skills and other ranged attacks. Primary Force Arrow and Fundamental Heartseeker are suitable for early games but might still find a use later on. Improved Barrage and Improved Rapid Fire will be the actual main attacks, while Mixed Cold Imbuement is to further synergize with the Cold Sorcerer.
Countering Smoke Cloud is mostly for utility as it can daze groups. Remaining skill points will be for important passives like Weapon Mastery, Concussive, Trick Attacks, Aftermath, Trap Mastery, and Second Wind. For a bit more defensive, choose Supreme Death Trap as the ultimate and Precision as the key passive.
The two main melee classes are the Rogue and Barbarian. The Rogue is more about evasion and quick hits. The Barbarian is, instead, a ferocious tank that is always at home in a crowd of monsters. Working together, they can deal will with most threats Diablo 4 has to offer.
The Barbarian's expertise is the Arsenal. This lets them gain bonuses while wielding specific weapon types. At level 15, players can add a different weapon's bonuses to their current one. It is recommended for this team-up to have some combination of Two-Handed Axe, Two-Handed Sword, One-Handed Sword, and Polearm.
The Barbarian will primarily use slashing weapons, allowing the use of Battle Flay, Violent Rend, and Furious Upheaval. To help the Rogue, one will want Power War Cry, Strategic Rally Cry, and Fighter's Steel Grip as options. These shouts are also excellent for Barbarian PvP builds in Diablo 4. Accompanying passives should feature Endless Fury, Guttural Yell, Quick Impulses, Prolific Fury, Cut to the Bone, Invigorating Fury, and Brute Force. Supreme Wrath of the Berserker is an excellent ultimate to help allies, and Gushing Wounds key passive will make bleeds even better.
The Rogue will need to switch its Diablo 4 build to perform in melee range. This includes grabbing Fundamental Blade Shift, Improved Twisting Blades, and Disciplined Dash. Blended Poison Imbuement can also be useful for this team-up. This Rogue will also be a bit more defensive with passives like Siphoning Strike, Reactive Defense, Rapid Gambits, Malice, and Alchemic Advantage. Supreme Shadow Clones is a good ultimate for dishing damage, while Momentum, as the key passive gains buffs from melee cutthroat attacks.