The Only Onslaughter Guide You'll Ever Need!

Welcome to my favorite way to play Amon in Borderlands 4! This guide is centered heavily around melee but has a lot of options when it come's to using guns as well. This build is capable of soloing UVHM 5 and is great as a leveling guide as you play through the game! There is an accompanied video which is linked on this page as well if you'd prefer that format and want to see the build in action.

Augments, Capstones, and Items

Starting out with the Augments

• Pyroclast: This is one of the first available augments and also one of my favorites. During Onslaughter, you're surrounded by a ball of fire that damages all enemies within range. Every kill you get increases the damage of this by 20%, up to 200% total. Not only that, but each kill now restores 20% of your AS duration meaning you can stay in Onslaughter permanently with enough kills!
• Thermal Diffusion: This is one 2 augments that I would advise against. Rocket Punch gains double radius, and increased damage based off of your max shield capacity. You can also choose to deal fire damage or cry with your melee, however it's entirely outclassed by the next augment.
• Fellfrost: Do not sleep on this augment. It's one of the best mobbing skills in his tree and allows Amon to one-shot the majority of enemies. After pressing the AS button (it doesn't work if you use the melee key for some reason) you can choose to press the AS button again to swing a giant cry sword in a large radius in front of you. This will instantly kill anything below 25% HP aside from bosses. Keep in mind, if an enemy is at 50% HP, and this drops them down to 22%, it will still count for the execute. This and Pyroclast are must-have augments for general mobbing.
• Force of Nature: I swap to this anytime I'm planning to fight a boss. Simply put, when you deal gun damage in Onslaughter, you apply stacks to the enemy. When you Rocket Punch, melee, or use a Forgeskill on the enemy, they explode doing heavy damage. The reason this comes into play is the fact that each stack detonates for 100% of the damage that was dealt. So if you stack Berserk and use Dragon's Breath while shooting an enemy with the Hot Slugger you might be able to do close to 60,000 damage per shot. If you can stack that up by shooting the enemy 10 times, you'll now do a 600,000 damage burst to them and nearby enemies if you use a Forgeskill to detonate the stacks. Absolutely insane damage augment.
• Fulminating Fist: You send out a shock lighting wave that can be spammed. I haven't used it much but it wasn't good when I did. I don't use this one.

Capstones

• Hoarcleave: This turns your Molten Hammer Forgeskill into a ranged cryo blade that penetrates enemies and instantly freezes anything it touches (including some bosses!). It has a short cooldown and is amazing at proccing your stacks from Force of Nature. Enemies also detonate when killed by Hoarcleave and it's great for activating Forged In Steel. I use this 80% of the time.
• Molten Roil: This is an upgrade for Molten Hammer. It essentially takes 40% of the damage you dealt to the enemy with the hammer and creates a fire pyre underneath them to release all of that damage. It's a good capstone and if you enjoy the hammer, definitely go with this.
• Stormcutter: I admittedly haven't used this one. To my knowledge it's quite powerful as it restores cooldown, restores duration if you're in AS already, and gives your ordnance back. The only real problem with this skill is that it requires you to fully go down the right tree which is by far the worst.

Items and Gear

• Luckily, Amon can use a wide variety of gear and I encourage you to try out things for yourself. If something looks interesting, use it! I've used just about everything on Amon and while some of it was less than stellar, most everything did just find killing the enemies, even in UVHM 5. However I will get into some specifics.
• For gun's you'll want to be looking for any sort of Jakobs shotgun. These are amazing on Amon since they have very high damage per shot. Keep in mind, this means that skills like Berserk or Dragon's Breath will be giving HUGE bonuses to your shots! Also they have direct synergy with Into the Fray as they will be dealing more damage at close range than normal. One of my favorite techniques is to play this sort of like Shotgun Zer0 from BL2. Activate your action skill, throw a nade, use your Rocket Punch to get close to the enemy, and use your shotgun to take them down.
• Any Jakobs shotgun will work, however I'd highly highly recommend the Hot Slugger (from the Callous Harbinger of Annihilating Death in Terminus Range), Rainbow Vomit (from Leader Willem in Carcadia Burn), T.K's Wave (from Rocken Roller from Carcadia Burn) or a shotgun with a spread launcher attachment if you want to become broken OP. You could also think about the Hellwalker (from Saddleback in Terminus Range) however it's been heavily gutted since it's debut in BL3 so it's honestly not great. It does play acool little guitar riff each shot tho :) also it spawns with mostly the same parts everytime, meaning it's pretty much just a decent purple Jakobs shotgun that can be farmed consistently.
• You can also try out automatic weapons, you won't be one-shotting but you will be having a lot of fun! One of my current favorites is the Wombo Combo (from the Rippa Roadbirds in Carcadia Burn) as it does high DPS, can come in any element, and shoots zip rockets that deal high damage meaning Berserk gets pretty big bonuses from it. Vladof underbarreled guns also work great, flamethrowers have obvious synergy, and underbarrel shotguns can do crazy high DPS.
• For repkit, look for anything with Hard Hitter as it'll add bonus melee damage for 6 seconds. If you plan to be fighting bosses, you may also want to look for an Amp repkit so you can increase your detonation damage with Force of Nature. Any purple kit will do, however you can also look for the War Paint (from Saddleback in Terminus Range) as it'll provide move speed and fire rate or the Triple Bypass (from Backhive in The Fadefields). The Triple Bypass gives 3 charges to your repkit and increases the duration of the effects, meaning you can potentially get 30 full seconds of bonus melee damage.
• For your ordnance, use anything you like but this build works best with grenades and specifically ones with a low cooldown or high charges. This is because we want to hit as many enemies with Gut Punch as we can for the weaken effect and we want to be activating Dragon's Breath whenever we can. My go-to grenades are the Jelly (from Splashzone in The Fadefields) or the Swarm (from Sidney Pointylegs in The Fadefields). The Jelly will do a lot more damage as a grenade but the Swarm will be much better at activating Gut Punch. You could also use a crit knife, however that'll likely get nerfed and I don't like being too broken so I avoid it.
• For classmods, you're going to want to look for literally anything buffing up the red tree or anything that provides bonuses to Forgeskills in the other trees. For legendary classmods you'll want either the Forge Master (from Radix in the Carcadia Vault) for more Forgeskill cooldown or the Furnace (from Idolator Sol in The Fadefields). The Furnace is going to be your best option as it converts Hoarcleave to fire and increases fire damage by a significant amount. The skills it buffs are amazing too, but you'll want to look for one that gives good boosts to both Mortal Flare and Dragon's Breath.
• For shields, be on the lookout for anything with the Berserker effect or any armor bases shield that grants melee damage on segment break. These shields provide a huge damage boost to each of your punches. Assuming you're far enough through the game you can get the Heavyweight (frome the Vile Prototype in Terminus Range) which will be your absolute best option. It doubles your melee damage assuming you have armor segments left but breaks the segments in the process. The math on this is multiplicative to my knowledge, meaning it can hit some absolutely crazy numbers! Other great options are the Firewerks (once again from Splashzone in The Fadefields) and the Super Soldier (from Vile Lictor in Terminus Range).
• The enhancements are 100% up to you and what you're using. Unfortunately it appears that the legendary enhancements can only be found as world drops so there's no reliable way to farm them. Look for one that buffs up whatever weapon type you use more, and pay attention to the smaller passives for anything spicy.

Gameplay Loop

• Most of the gameplay loop will end up playing out the same. Always remember to change your augments on the fly to provide whatever you need at the time. Anytime you AREN'T fighting a boss, put on either Pyroclast or Fellfrost for some crazy mobbing potential (you could also use Force of Nature but it's very overkill). Now once you enter a mobbing area, always start by using your Forgeskill to proc Berserk. Aim for as many kills as you can to achieve higher stacks of There Is Only Red. Enter your Onslaughter and start swinging. For Pyroclast based builds you'll want to be swinging, throwing nades, and shooting anything you're close/can't punch the enemy. Remember that Dragon's Breath will always proc simply by throwing a grenade (it doesn't even have to hit anything) and it has no cooldown, spam it as much as you can to keep your damage up. Your goal with Pyroclast is to continue getting kills to increase your Onslaughter timer and stay in your AS permanently.
• If you're running a Fellfrost build it's gonna be a lot easier. Simply activate Onslaughter, find an enemy, press the AS button, press it again after your Rocket Punch, and everything should die. Remember to always try and keep Berserk up by getting kills, it's one of your biggest damage bonuses. Also when using Fellfrost you can swing your camera around to hit all sorts of enemies with the second swing, it'll always execute enemies below 25% which should mean a Rocket Punch into Fellfrost combo should kill pretty much every mob every time.
• For bossing, make sure you swap to Force of Nature. Ideally you have a high damage shotgun to stack this up. Enter the arena, use an Amp repkit if you have one, activate your Forgeskill to proc Berserk, activate Onslaughter for bonus damage and to be able to stack Force of Nature, then throw a grenade. You're now fully ready to shoot the enemy. Shoot at the boss while still in your AS (aim for the crit), if this gains you 10 stacks of Force of Nature (which can be viewed above the healthbar) then you're ready to Rocket Punch them and detonate all of the stacks. After that, throw another nade, shoot again, Rocket Punch again. If you're using something like the Hot Slugger, you're gonna use a similar but different approach. Since the Hot Slugger only shoots one projectile, the enemy will only accumulate 1 stack at a time, so you'll need to manually continue shooting them for more stacks. Enter arena, repkit, use your Forgeskill, activate Onslaughter, throw nade, shoot Hot Slugger (at the boss crit spot if possible), throw nade, shoot Hot Slugger, throw nade, shoot Hot Slugger, rinse and repeat until at least 5 stacks, then Rocket Punch.
• If you're using a spread launcher for bossing, do the same as instructed above, but this time you only need to shoot once and punch once. It should be enough damage to one-shot the majority of bosses assuming you land all shots of the spread launcher.

In Conclusion

That is the end of this build. I really really hope you were able to learn something from this. Please experiment with different guns, different skills, different shields, etc. Player creativity is what discovers all of the fun builds we get to try out!

Super duper huge thanks to DominicTheChemnerd for absolutely carrying me through all of this information and teaching me how almost every one of Amon's skills work! Moxsy has some great videos online if you're interested in checking out some really broken glitches on Amon, and I stream a bunch if you wanna see some gameplay :)