So, I had this idea for multiclassing a Battlerager Barbarian and Armorer Artificer. I am wondering if this has potential to make up for some of the weaknesses of the battlerager, or if its just a weird multiclass build that could be fun but has no real synergy. The build I have in mind would be Barb (17), Artificer (3). 

Pros:

• Spiked Armor can become Arcane Armor, which means you effectively get a full body suit of spiked armor, which is fun to imagine at the very least
• Infusions could be used to give a +1 to your AC (bringing the max to 17 instead of 16) and make your primary weapon magical 
• Assuming dwarven restriction, the infiltrator armor could bring your speed up to 30 feet and gives you a ranged attack option that doesn't require you to drop your melee weapon and isnt casting a spell (i.e you can do it while raging) 
• Spells offer utility outside of combat, and most utility spells wont require you to have a high spell attack bonus or save DC (can keep Int to a minimum)  

Cons

• Have to ensure at least a 13 in Int, making this build a little MAD if you want a good Str, Con, and at least a 14 in Dex for your armor bonus
• Give up the Barb Capstone and one other main class abiltiy, sad times
• Does not pair well with the Defensive armor type, as you will almost never use the Thunder Gauntlets over a great weapon AND the defensive field temp HP would overlap with the temp HP you get from your 6th level Battlerager feature

Thoughts? 

It's a big MAD like you say, but probably manageable.

Regarding the pairing with the Guardian armour model, the gauntlets actually let you attack using Intelligence, so if you don't mind running a build with lower Strength then this could help with MADness. While the temporary hit points do conflict with those from the battlerager, the defensive field gives more protection and while you're using it you don't need to use Reckless Attack which may be beneficial sometimes. One other interesting feature of Guardian for a Barbarian multi-class is that the Thunder Gauntlets make you an even more inviting target as a tank (which you want in order to shield the rest of the party) as if you strike recklessly with them, then enemies end up with a choice of disadvantage vs. your allies, or advantage vs. you.

Also a note that for speed, as an Artificer you also have access to Longstrider from 1st level, it lasts an hour and requires no concentration, so if you cast it before raging it will stay in effect; this lets you double down on the Infiltrator speed bonus, or get some with Guardian instead.

I think it could be a lot of fun to play, despite the flack that Battlerager gets.

Yeah. Although, part of me is also wondering if it would be a better build to do with more Artificer instead of barbarian. Like invert it and make it a 17 Artificer 3 barb. You get just enough levels in barb to pick up rage, the spiked armor, and a few other goodies and then build the rest in Defensive model armorer. Then there is no overlap with the temp HP and you can eventually invest more in infusing your spiked armor. The thunder gauntlets offer some nice versatility where you can use your higher Int score when not raging, and when you are raging you could use maybe switch to using Str, as your rage bonus to damage might make up for the lower score. Or you could invest more heavily in Str and just have less spells and uses of certain Artificer features. I don't see this build requiring a bunch of feats to make it work, so more of your ASIs could be put to making sure your main few stats are high. 

Quote from Kaboom979 >>

invert it and make it a 17 Artificer 3 barb

That's a good option as well; you get Rage and Reckless by 2nd level, the other things you lose this way are the extra hit points of the barbarian (d12 hit die vs. d8), plus increases to rages per day and rage damage, but you have a bunch of other options as an Artificer to balance it out if you need to.

There are very few martial focused builds that don't work well with a few levels of Barbarian added for extra durability and recklessness. 😉

Ack, I always forget Reckless Attack is also tied to Strength attacks, I keep thinking it's just the Rage damage, in that case you're right to want Strength as well, though it probably means trading off against Intelligence; Intelligence for an Artificer is important but not critical, as you can pick spells that don't rely on the attack modifier and save DC, which ought to be fine as you will probably prefer buffs with no concentration (Armorer's Mirror Image is great for that) and maybe some for out of combat utility? Beyond that there are two features that really want INT: Flash of Genius (7th level, add INT to an ability check or save for you or an ally, up to INT times a day), this is a nice feature, but you'll get Danger Sense (advantage on DEX saves) from Barbarian which will cover quite a few saves already, Spell Storing Item (11th level, store 1st or 2nd level spells in up to 2xINT items that can be used INT times each): This is fun for handing out spells your non-caster party members can use. While you can use both features for yourself, they're ideal for party support, but if you're already tanking damage and keeping enemies at bay then you may think they're getting enough from you?

One other thing to consider is what else your group may contain; if you're going to have a good healer like a Cleric or Paladin, or even just another front-line melee character, then you can probably get by with a Constitution of +2 early on, as it takes the pressure off you to have maximum hit points, and the temporary hit points will help your own HP go further, this should then allow you to max Strength and Intelligence more easily if you want to go that route, since you only need +2 in DEX if you don't get Medium Armor Master.

I had this same idea but atleast 9 Articifer and the rest barb.

Taven brawler feat works well to bonus action grapple with spiked armor 👌 

I actually have just started playing this character. At this point, I have 3 levels in Battlerager and plan to multiclass into Artificer from this point forward. Thanks to my DMs stat determination method, I have pretty good scores to work with. Right now I have an 18 in Str, a 14 in Dex, and a 14 in Int. My Con score is decent as well, but I dont recall my score for that. Either way, I am playing a Hill Dwarf so my HP should be fine. 

At this point, it will take me another 3 levels to determine which type of Armor Model I want to go with. I am conflicted. 

Guardian:

• The thunder gauntlets are a good weapon option with a rarely resisted type. They would allow me to keep my hands free for grappling and keeps me in melee range for my B.A spike attack (so there is good synergy with the spiked armor). Being melee weapons, I could use my Strength and still benefit from rage damage and reckless attack. 
• Being able to pump some temp HP would go pretty far while raging

Infiltrator

• As a dwarf, my movement speed is only 25 so the 5 foot boost would be nice to have
• Since spiked armor imposes disadvantage on Stealth checks, this would allow me to cancel that out without needing to pick up Medium Armor Master
• The lightning launcher gives me a ranged weapon option that I can use to deal lightning damage and works while I am raging. This it tempting because I could mix up attacking people with a melee weapon and making ranged attacks if my next target is too far away to reach that turn, and I would not have to drop or switch weapons to do so. 
• Also, this is a pirate-themed campaign, so having a consistent ranged option might be good for ship combat if we are not close enough to board an enemy ship. 

I would say I am leaning more towards the Guardian as I think it synergizes better with Barbarian, but at the same time Infitrator is tempting because it would give me more options for mobility and attacking. 

Quote from Kaboom979 >>

I would say I am leaning more towards the Guardian as I think it synergizes better with Barbarian, but at the same time Infitrator is tempting because it would give me more options for mobility and attacking. 

Why not both? One of the benefits of Armorer is you can switch your Arcane Armor type, and doing so only requires a short rest to reconfigure it. If you know you're likely to be fighting in close quarters, switch to Guardian, then default to Infiltrator when you know you're on recon, or you're just not sure.

You could theme it like removing some of the sections of the armour, e.g- around the arms in particular since you're switching to/from thunder punch?

Quote from Haravikk >>

Quote from Kaboom979 >>

I would say I am leaning more towards the Guardian as I think it synergizes better with Barbarian, but at the same time Infitrator is tempting because it would give me more options for mobility and attacking. 

Why not both? One of the benefits of Armorer is you can switch your Arcane Armor type, and doing so only requires a short rest to reconfigure it. If you know you're likely to be fighting in close quarters, switch to Guardian, then default to Infiltrator when you know you're on recon, or you're just not sure.

You could theme it like removing some of the sections of the armour, e.g- around the arms in particular since you're switching to/from thunder punch?

 Thats a good point. Forgot they could reconfigure so quickly

Quote from acehole131 >>

I had this same idea but atleast 9 Articifer and the rest barb.

Taven brawler feat works well to bonus action grapple with spiked armor 👌 

 Unfortunately, Tavern Brawler doesnt add much because the armor only works well for grappling when you grapple as part of your Action. 

Additionally, when you use the Attack action to grapple a creature, the target takes 3 piercing damage if your grapple check succeeds.

The good news is you can substitute one attack as part of you Action with a grapple and then use the spiked armor to attack as a bonus action. 

That's a bit too literal. 

Grapple as an action because 99.9 percent of the time you can only grapple as an action. 

The feat allows for a bonus action Grapple.

Shouldn't matter action or bonus action, your still grappling....

Quote from acehole131 >>

That's a bit too literal. 

Grapple as an action because 99.9 percent of the time you can only grapple as an action. 

The feat allows for a bonus action Grapple.

Shouldn't matter action or bonus action, your still grappling....

 

 

 the ability specifically says it triggers when you use the Attack action to grapple

if you grapple as a bonus action, it is not associated with the Attack action, which is its own specific entity. While there are lots of ways to make attacks outside of the Attack action, there are also alot of abilities that only work if those attacks are part of that specific actionl

Quick update on where this is at. My character has reached level 4 and I have taken my first level in Artificer following barbarian. I am pretty pleased with the Armor Spike attack bonus action. Since I am prolonging getting Extra Attack with this multiclass, I am happy to still be able to make 2 attacks per round using my primary weapon and the armor spikes. The damage for the armor spikes isnt optimized by any means, but since the majority of the damage is coming from my Str modifier and Rage Damage bonus, its still a very reliable chunk of extra damage every round. 

As far as spellcasting is concerned, I definitely want to keep a strong wall between being more melee weapon focused in combat and spellcasting out of combat. So I am trying not to pick up any spells that require attack rolls, saving throws, or concentration and mostly looking for buffs I can apply to myself before combat begins. With first level, I have picked up Cure Wounds, False Life, and Longstrider. I see extra temp HP from False Life going a long way with raging. Cure Wounds is good for patching up outside of combat, and in combat if I get knocked down I envision that if a teammate picks me back up I can quickly give myself some extra HP and then use my bonus action to start a new rage. Longstrider is nice because I am a dwarf with only a 25ft move speed. 

The only attack spell I have grabbed at this point is the Thorn Whip cantrip. This is nice because a) I think it fits pretty thematically with the spiked armor, being able to throw out a long, pointy whip and b) I envision this being helpful in the scenarios where I do not have quite enough movement to get into melee range of the enemy and I could potentially try pulling one into my melee range and separating them from their friends right at the start of combat

Now, of course, waiting until level 4 or 5 to multiclass might have been the smarter choice, but since I am building this character up level by level I wanted to start getting some of the goodies from Artificer sooner rather than later. Its not the most optimized choice, but I am having a fun time so far. 

Was loving the updates on this build! 

I think that this is an interesting build and as a whole the concept fits rather nicely. Is there an update on this build?

Side note. I would guess that magic tinkering would work with the individual spikes on the armor. 

 Sadly the character perished in an act of self-sacrifice in the campaign. Overall, with the point the character reached, I was pleased with the result. I hope I can revisit some version of this build in the future, maybe for a Tier 2 or higher oneshot where I can better get a feel for potential synergy. It was functional at lower levels thanks to certain aspects of each class making up for the losses from multiclassing, but I felt it might have worked better later on.