Barbarian is the best class to make use of the unique swords you find in Diablo 4. These unique items are all about doing an insane amount of slashing damage to cut enemies down to size.
As with the other unique items in D4, unique swords will only start dropping after you have unlocked (and are playing) World Tier 3 or higher. Keep running dungeons for a chance to see them drop.
Doombringer (General)
Doombringer returns to Diablo 4 as a unique sword after appearing among unique items in all of the previous three installments.
Its unique effect increases your shadow damage against all nearby enemies while reducing the damage done to you by them in return for a few seconds.
Doombringer also increases your core skill damage, critical strike damage, and overall damage to boost your shadow output.
You, furthermore, gain bonus life points as well as a chance to heal yourself on every hit.
Fields of Crimson (Barbarian)
This unique sword is a two-handed sword that is confined only to the Barbarian class. It means no other class can benefit from it.
This item is very deadly because if you hit your enemy with a rupture, it will create a blood pool and will cause depleting their health for quite some time. Moreover, if any other enemy stands in the blood pool, they will have their health depleted too.
Other affixes that this sword offers are also very interesting. It reduces the rupture cooldown, enhances the damage inflicted by two-handed slashing weapons, and increases the ranks of rupture.
Ramaldani’s Magnum Opus (Barbarian)
This unique sword does insane damage to close enemies. All the skills that you have will inflict more damage per point of fury if you have Ramaldani’s Magnum Opus in hand. But the downside is, you will lose 2x fury each second.
This makes Ramaldani a bit difficult to use but once you get used to it, you will start utilizing it to the fullest.
Other affixes that this unique item offers include a fast striking rate, more damage, more critical damage, and restoring primary resources.
The Grandfather (General)
The Grandfather is a non-class exclusive unique two-handed sword in Diablo 4. If your build is focusing on doing as much damage as possible, you are going to find a great use for this.
The Grandfather unique sword increases your critical strike damage and your overall damage. All of your stats get bonus points as well which helps increase your damage further.
Its unique effect can potentially double your critical strike damage as a permanent passive.