How to Add a Fourth Legendary Mod in Fallout 76 is now a real option for Fallout 76’s specially tagged unique weapons and armor. The Slasher update changed Unique Item Crafting so those items can have their Legendary Mods changed and can also receive a fourth Legendary Mod at a workbench.
This is one of the biggest build-crafting changes in the September 15 update because it applies to a huge catalogue of named gear. Bethesda says more than 80 unique named weapons are part of the wider system, giving old rewards a reason to come back out of the Stash. Our Unique Weapon Crafting guide covers the broader feature.
How to Add a Fourth Legendary Mod in Fallout 76 at a workbench
For How to Add a Fourth Legendary Mod in Fallout 76, take an eligible unique weapon or armor piece to the appropriate workbench and open its Modify options. Unique items are now explicitly tagged as unique when inspected, which helps confirm that the item is part of the new system.
From the Legendary Mod options, you can change the existing Legendary effects and use the fourth-star slot where the item supports it. You still need the relevant mod available to your character; the update does not simply hand every four-star effect to every player. The confirmation window now also shows which mod will be replaced and warns you if the outgoing mod is not known by your character.
How much does a fourth Legendary Mod cost?
The Scrip rules matter when learning How to Add a Fourth Legendary Mod in Fallout 76. Bethesda changed ordinary Legendary Mod replacement costs to a fixed amount: one-, two- and three-star mod changes use 50 Scrip, while a four-star mod change uses 100 Scrip as the base cost.
Unique items have a special premium on top of those values. Bethesda says changing Legendary Mods on unique gear costs ten times the base Scrip cost. That makes unique-item customization substantially more expensive than adjusting normal legendary gear, so it is worth checking the workbench confirmation before committing a valuable mod.
Can every unique weapon get a fourth star?
How to Add a Fourth Legendary Mod in Fallout 76 applies to items classified by the game as unique under the new system, but that does not mean every random weapon in your inventory qualifies. The September update specifically expanded crafting for named unique weapons and armor, and those items now display a unique tag when inspected.
Bethesda also gave many named weapons their own unique effect in the same update. Examples include Holy Fire, Elder’s Mark, Nuka-Launcher, Ticket to Revenge, The VATS Unknown, Grand Finale and dozens more. The unique effect is part of the item’s identity, while the Legendary Mod slots give you additional build control.
What happens to the original unique effect?
The point of How to Add a Fourth Legendary Mod in Fallout 76 is not to turn a named weapon into a completely generic legendary. The update gives unique gear more flexibility while retaining the special effect that makes that item different. You are modifying Legendary Mods around the item’s unique identity rather than deleting the reason it exists.
Bethesda also changed default paint handling so you can always craft the paint mod an item originally spawned with, even if you do not know that paint plan separately. That means experimenting with a unique item’s appearance does not permanently lock you away from its original look.
How to Add a Fourth Legendary Mod in Fallout 76 without mixing up the costs
While How to Add a Fourth Legendary Mod in Fallout 76 is mainly about the fourth-star slot, the same update increased the cost of crafting unique items themselves. Bethesda says three-star unique items require 40 Vault Steel and 30 Legendary Modules, while four-star unique items require 80 Vault Steel and 65 Legendary Modules.
Those are crafting costs for making the unique item, not the same thing as the Scrip charge for swapping a Legendary Mod. Keeping those currencies separate will save you a lot of confusion at the bench.
How to Add a Fourth Legendary Mod in Fallout 76 and decide if it is worth the cost
For a named weapon you already use, How to Add a Fourth Legendary Mod in Fallout 76 can be a major upgrade because it lets you keep the weapon’s special identity while adding another high-end effect. The catch is the cost. Unique items deliberately charge much more Scrip for Legendary Mod changes, so testing the build on paper before spending is sensible.
The Slasher update has effectively turned dozens of old named drops into genuine endgame crafting projects. If you have a favourite unique sitting untouched because its original legendary roll never suited your build, How to Add a Fourth Legendary Mod in Fallout 76 is now the route to making that weapon useful without abandoning what made it unique in the first place.
For official Fallout 76 information, visit the Fallout website.
