☆ How Rush Saved Mercenary Day (Bounty Pack 1)
★ 12 active SHiFT Codes as of December 4, 2025
☆ Black Market Location
★ Elemental Weakness Chart
☆ Legendary Weapons
★ Builds: Vex | Amon | Rafa | Harlowe

The Corroding Arc-Knives Rafa build focuses on maximizing the damage, duration, and healing of the Arc-Knives in Borderlands 4. See the best builds, skills, weapons, and gear to use for Rafa, along with the best skill tree abilities and character playstyle.
| All Rafa Guides | ||
|---|---|---|
| Best Builds | Cosmetics | Skill Trees and Voice Actor |
| Leveling Build | Boss Farm Build | Arc-Knives Build |
| Ricochet Build | ||
List of Contents
|
・ Action Skills – Arc-Knives Melee Attack Damage increased by 12% Dash Damage increased by 5% ・Passives – This Year’s Gimmick Handshake Deal: Melee Damage increased to 9% from 7% per point Empuje: Action Skill Duration increased to 7% from 6% per point |
Note: Only Changes that affect this build are listed above
With the October 2 update, additional buffs were given to Rafa, which target some of his active and passive skills.
For the Corroding Arc-Knives Build, Handshake Deal and Empuje both received buffs, allowing Rafa to deal even more damage with his Action Skill, on top of the Melee Attack and Dash Buffs received by Arc-Knives!
October 2 Update and Patch Notes
| Strengths | Weaknesses | ||||
|---|---|---|---|---|---|
|
✔︎Great damage and healing ✔︎Effectively unlimited skill duration ✔︎Great for both bosses and mobs |
✖︎Lack of range while using Arc-Knives ✖︎Fight For Your Life cuts skill short ✖︎Can be taken down by burst damage |
The Corroding Arc-Knives build provides great damage and healing which, when partnered with its effectively unlimited skill duration, will allow you to continuously dish out massive amounts of damage. This makes the build perfect for taking down bosses and mobs of enemies.
The downside of running this build, however, is that you are lacking in range, which makes it harder to damage flying or distant enemies. Not only that, but you can get taken down by burst damage if you are unable to quickly heal up, especially in lower levels. Lastly, if you do get taken down and enter Fight For Your Life, your Action Skill gets cut short, lowering your damage output and making you vulnerable to attacks.
| Action Skill | Arc-Knives |
|---|---|
| Skill Tree: This Year's Gimmick | |
When using this Action Skill, Rafa stows away his guns and wields a pair of Arc-Knives. While the Ark-Knives are drawn, Rafa switches to full melee combat, slicing, dicing, and dashing his way through enemies. Reactivating the Action Skill makes Rafa perform a Blade Fury, dealing a lot of damage and ending the Skill.
| |||
| Skill Tree | Priority Skills | ||
|---|---|---|---|
This Year's Gimmick | Handshake Deal Rafa gains increased Gun Damage and Melee Damage Midnight Oil Rafa's Action Skills deal Bonus Corrosive Damage. The longer the Skill has been active, the greater the Bonus Damage. Dial In Whenever Rafa damages an enemy with a Melee Attack, his Melee Attacks gain Critical Hit Chance. This chance stacks, and all Stacks are removed whenever Rafa Critically Hits an enemy. Saldar Rafa's Melee Critical Hits gain Lifesteal. El Borracho Rafa deals increased Corrosive Damage while his Action Skill is active. The longer it has been active, the greater the bonus. This effect can stack. Empuje Rafa gains increased Action Skill Duration. Cruel Accrual Rafa gains increased Skill Damage with all Skills. The longer his Action Skill has been active, the greater the bonus. This effect can stack. | ||
| |||
| Skill Tree | Priority Skills | ||
|---|---|---|---|
Remote Agent | Shield Barriest Overdrive Skill. Rafa gains increased Shield Recharge Rate and improved Shield Regen Delay while Overdrive is active. Juerga Whenever Rafa Critically Hits an enemy, Action Skill Duration is restored. Resiliencia Overdrive Skill. Rafa gains increased Damage Reduction while Overdrive is active. | ||
The best skills for the Corroding Arc-Knives Rafa Build revolve around maximizing the Arc-Knives' damage and duration, as well as giving him survivability since he will be in melee combat the entire time.
The passive skills you get from the Remote Agent Tree will give Rafa survivability, as well as Action Skill Duration whenever he performs a Critical Hit.
From Levels 1-30, your goal is to stack points in the This Year's Gimmick Tree until you unlock Altered Cabron and Galvanic Panic. Once Galvanic Panic is unlocked, with the skills leading up to it, you should reach a point where you can effectively clear encounters alone.
From Level 31 onwards, take skills that will improve your survivability and Active Skill Duration. Both Shield Barriest and Resiliencia improve your survivability while in Overdrive mode, while Juerga lets you restore Action Skill Duration whenever you perform a Critical Hit.
| Augment | Effects |
|---|---|
Altered Cabron
|
• Provides Healing on kills • Gets Bonus Corrosive Damage and Movement Speed whenever Rafa heals |
Altered Cabron provides Rafa with Healing, Bonus Damage, and Movement Speed, three things that he will need whenever he has his Arc-Knives equipped. This lets him weave in and out of danger easily, while dealing a lot of damage and healing whenever he kills an enemy.
Galvanic Panic
|
||
| Tree |
This Year's Gimmick
(Branch 3) |
|
|---|---|---|
| Effect | ||
| Whenever Rafa performs a Melee Attack while Arc-Knives are active, fire an Acid STRM Glider at an enemy in his view. Acid STRM Gliders deal Corrosive Splash Damage based on the number of total Marked enemies. Additionally, killing an enemy while Arc-Knives are active restores Action Skill Duration. Activating Blade Fury causes Rafa to fire a volley of Acid STRM Gliders in front of him and end Arc-Knives. | ||
One of Rafa's weaknesses when he wields his Arc-Knives is his range, preventing him from easily attacking flying enemies. Galvanic Panic solves this problem, as performing a melee attack fires an Acid STRM Glider at an enemy Rafa can see. This lets you target and attack nearby flying enemies, covering for his weakness.
| Jump to a Section! | |||||
|---|---|---|---|---|---|
| Weapons | Repkit | Ordnance | |||
| Class Mod | Shield | Enhancement | |||
| Firmware | |||||
Any Legendary weapon can work for Rafa, as you will mostly be using his Arc-Knives in fights. Done right, you will be in melee combat in every encounter. The only time you will be forced to use your gun is when you enter Fight For Your Life. As such, use any Legendary Weapon you are comfortable with.
Some Legendary weapons that you can equip are Bonnie and Clyde for access to both mid-range and short-range options, as well as the Linebacker for a powerful explosive weapon.
As mentioned above, your Arc-Knives are your primary source of damage, and your gun will only see use once you enter Fight For Your Life. As such, use whatever Manufacturer you like for your weapons as long as they are capable of taking down an enemy quickly during Fight For Your Life. We recommend using Jakobs or Vladof weapons, as they can dish out a lot of damage in a short amount of time.
Since you will mostly be in melee combat with your Arc-Knives,use the weapon type you are most comfortable with. We do, however, recommend Shotguns, Submachine Guns, and Assault Rifles as you will want to be in short to medium range when engaging enemies. This will let you get back into the fight faster.
| Repkit | Unique Trait |
|---|---|
![]() Shiny War Paint |
Chrome: On use, grants +30% Fire Rate and +30% Movement Speed for 15s, and reduces Repkit Cooldown by 2s each time Damage is taken. |
Because the build provides a lot of healing already, using a Repkit with other passive effects is ideal. Although you can't use Shiny War Paint's increased Fire Rate, its +30% Movement Speed will help Rafa go from target to target easily.
Try to get a Shiny War Paint that provides other passives that may prove helpful, such as increased Duration or increased Melee Damage.
| Ordnance | Unique Trait |
|---|---|
![]() Slippy |
Swordfish: Deals Melee Damage on detonation. |
Although Rafa cannot use Ordnances with his Arc-Knives out, you can still equip and use Slippy as it deals Melee Damage, which will make it benefit from Rafa's Passive Skills.
Use Slippy to quickly kill enemies while outside of Arc-Knives mode, as well as when you need to break Vile Crystals on Vile Enemies.

The Esgrimidor is the best Class Mod when using the Arc-Knives as it improves the Critical Hit Chance of your Melee Attacks. Additionally, whenever you perform a Critical Hit with Melee Attacks, you restore Action Skill Duration.
As this build maximizes the Critical Hit Chance of the Arc-Knives, you can keep refilling your Action Skill Duration, effectively staying in Arc-Knives mode during an entire fight or encounter.
| Shield | Unique Trait |
|---|---|
![]() Heavyweight |
Bareknuckle: On Melee Hit, consumes an Armor Segment to grant +100% Melee Damage. When Armor Shield is empty, grants +50% Melee Damage |
The Heavyweight is perhaps the best Shield to use for Rafa thanks to the increased Melee Damage that it provides, be it when consuming an Armor Segment, or when your Armor Shield is empty.
Although this may seem dangerous because of the Shield constantly getting depleted, the build provides enough healing for Rafa to survive, even without shields.
As the weapon that you will use in this build is based on personal preference, use whatever Enhancement improves your equipped guns. Try to get Enhancements that have passives that increase Melee Damage.
| Firmware | Set Bonuses | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Action Fist | Melee Damage is increased by 15% | Action Skill Damage is increased by 10% | On Melee kill, Action Skill Damage is increased by 25% for 8s | ||||||||
| Reel Big Fist | Melee Damage is increased by 15% | Melee Damage is increased by an additional 25% | |||||||||
The Action Fist Firmware is the best for the Corroding Arc-Knives build as it provides +15% Melee Damage and up to +35% Action Skill Damage, which both apply to the Arc-Knives.
Afterward, equip 2 pieces of Reel Big Fist, which provides an additional 40% Melee Damage.
| Specialization | Effect |
|---|---|
Bear Arms
|
Melee Damage now benefits from increases to Gun Damage. |
Now With Caffeine
|
Reduce Action Skill Cooldown whenever a Repkit is activated. |
I Am A Gun
|
Action Skill Damage now benefits from increases to Gun Damage. |
A Honed Mind
|
Action Skills gain a chance to Critical Hit enemies, and also gain increased Action Skill Critical Hit Damage. |
We recommend taking the following Specializations, investing first in Runner for Bear Arms. Afterward, invest ten points each in Runner and Sharpshooter to unlock the Daredevill branch. Once it is available, invest points in it until you unlock all of its Passives, namely Now With Caffeine, I Am A Gun, and A Honed Mind.
These Passive Skills will buff your Melee Damage, as well as the effectiveness of your Action Skill, making them hit harder whenever they are activated. Additionally, the points you invest in the different branches provide Melee Damage and Movement Speed, as well as Gun Reload Speed, Accuracy, and Action Skill Cooldown Rate.
Once you have the needed Passives, invest more Specialization points into Runner for more damage and Survivor for survivability.
Always start fights by pulling out your Arc-Knives. As soon as you are near an enemy, equip your Arc-Knives and perform a lunge attack to start the fight. This lets you jump into the thick of things immediately and start attacking.
While your Arc-Knives are equipped, you become vulnerable to enemies shooting from afar. As such, you have to keep moving to dodge attacks from distant enemies, as well as close the distance to nearby targets. Always be on the move to make yourself a hard target and to seek out new enemies to defeat.
Barrels are capable of dealing large amounts of damage to both you and your enemies. However, as you are in melee range, accidentally hitting a barrel with your Arc-Knives can easily put you in Fight For Your Life mode.
As such, always be aware of your surroundings, and keep your distance from any exploding barrels.
Be it for levelling Rafa, or for farming bosses, this build can do them both. As long as you can attack enemies, be it a crowd of mobs or a singular boss, you will be able to stay in Arc-Knives mode indefinitely.
If you are facing difficulties in using this build for either of these purposes, consider checking out our dedicated Leveling Build and Boss Farm Build!

Best Builds for Each Vault Hunter
| Character | Build |
|---|---|
Vex |
|
Rafa |
|
Amon |
|
Harlowe |
This build takes ages to kill a boss, the damage still isn't what it's supposed to be, it should take no more than 2 hits to kill a single bar, it's fun against enemies but bosses it's tedious, so don't say this build can work on bosses because it's horrible. Yeah you can stay in arc knives indefinitely but that doesn't help when the damage even with 123% melee damage should be this low, even after the buffs he got recently, it's just underwhelming and weak
Corroding Arc-Knives Rafa Build



Genshin Impact Walkthrough & Guides Wiki

Umamusume: Pretty Derby Walkthrough & Guides Wiki

Where Winds Meet Walkthrough & Guides Wiki
Honkai: Star Rail Walkthrough & Guides Wiki

Digimon Story: Time Stranger Walkthrough & Guides Wiki

Wuthering Waves Walkthrough & Guides Wiki

Chaos Zero Nightmare Walkthrough & Guides Wiki
Pokemon TCG Pocket (PTCGP) Strategies & Guides Wiki
Pokemon Legends: Z-A Walkthrough & Guides Wiki

Elden Ring Nightreign Walkthrough & Guides Wiki
Yu-Gi-Oh! Master Duel Walkthrough & Guides Wiki

Fire Emblem Heroes (FEH) Walkthrough & Guides Wiki

Diablo 4: Vessel of Hatred Walkthrough & Guides Wiki

Elden Ring Shadow of the Erdtree Walkthrough & Guides Wiki
Super Smash Bros. Ultimate Walkthrough & Guides Wiki

Monster Hunter World Walkthrough & Guides Wiki

Pokemon Brilliant Diamond and Shining Pearl (BDSP) Walkthrough & Guides Wiki
The Legend of Zelda: Tears of the Kingdom Walkthrough & Guides Wiki

Persona 3 Reload Walkthrough & Guides Wiki
Cyberpunk 2077: Ultimate Edition Walkthrough & Guides Wiki
©2025 Gearbox Software. Published by 2K Games. Developed by Gearbox. Gearbox, Borderlands, and related logos are all trademarks of Gearbox Software, LLC. 2K and the 2K logo are trademarks of Take-Two Interactive Software, Inc. All other marks and trademarks are the property of their respective owners. All rights reserved.
The copyrights of videos of games used in our content and other intellectual property rights belong to the provider of the game.
The contents we provide on this site were created personally by members of the Game8 editorial department.
We refuse the right to reuse or repost content taken without our permission such as data or images to other sites.
Its funny how the only boss you showed you fighting in the video was a boss with a yellow health bar that corrosive is strong against. I just switched to this build and you got me killed like 4 times fighting Callis which I would have destroyed which my previous build. Dont recommend this build it will get you killed on UVH 1 and above, stick with their peace breaker cannon build or i don't know think of your own build and don't rely on lazy build makers that hardly do any testing, and post it.