The Berserker Barbarian's frenzy is kind of a divisive topic. Rather than talk about fixing it, or whether or not it needs fixing, let me just offer a complete alternative that appeals to the self destructive rage monster theme:

The extra attack of frenzy comes at the expense of HP, and can be stacked exponentially. Your Berserker can make one extra attack at the cost of 10 hp, a 2nd extra attack at the cost of 25 hp, and a 3rd at the cost of 125 hp. Those numbers could be adjusted for balancing reasons, but the point is that your barbarian can push themselves so hard that the self destruct in a ball of furious vengeance, either going down or outright dying. Or, they can contain their fury for the long haul. 

No mucking around in exhaustion levels. 

I'd rather the exhaustion. Decreasing HP as a feature when already in combat as a tank taking HP loss from enemies is just going to down you instantly or relies on a cleric being the overdone "dedicated healer" if they are in party.  A couple levels of exhaustion is no big deal for a barb, and doesn't make you easier to take down.

Quote from Cyb3rM1nd >>

I'd rather the exhaustion. Decreasing HP as a feature when already in combat as a tank taking HP loss from enemies is just going to down you instantly or relies on a cleric being the overdone "dedicated healer" if they are in party.  A couple levels of exhaustion is no big deal for a barb, and doesn't make you easier to take down.

 Just like the original frenzy, you can just choose not to use it most of the time, or just use its lowest grade. But when you use it, its a cost you can mitigate with short rests that doesn't follow you around over the course of sessions, just being a drag. 

And with rage and d12 hit dice, a barbarian can take it. Its just not free. 

How about if the numbers were adjusted: it starts as 5hp, and the cost triples for each extra use that turn? so 5, 15, 45, etc.

I don't agree to hit points being used as a resource in this manner, period, regardless of what value. I don't agree that the cost of the feature should be mitigated by short rests - that's too much of a benefit to an already powerful ability, the whole reason exhaustion was used was so you could not just keep using it again and again throughout the day by short resting.

Exhaustion frankly seems the perfect choice. And there's ways to mitigate it. Greater Restoration spell can get rid of exhaustion, it's a 5th level spell and available to Clerics, Bards, Druids, Celestial Warlocks, Divine Sorcs and Artificers. If one is in your party, consider getting a ring of spell storing, they can store a spell and give you the ring, then you can just remove a level of exhaustion as an action.

If you're going to replace the exhaustion it needs to be something that is equal - and a HP cost is simply not.

I agree with CM: exhaustion is important.

I go the other way, from you, on my thoughts of how to improve Frenzy--make it worth racking up exhaustion levels. One weapon attack as a bonus action? That's very easy to get from other sources. If your campaign allows feats, Polearm Master & Great Weapon Master are the two most likely candidates. Magic items are another likely source, and there's always good 'ol fashioned Two-Weapon Fighting if that's your cup of tea.

Point being, if you can reliably get a bonus action weapon attack from other sources, Frenzy is just... blah. Why bother? At bare minimum, I think Frenzy needs to provide an additional bonus to Rage Damage. That alone would make it more attractive to use even if you don't need the bonus action.

It should also allow you to ignore the effects of any levels of exhaustion you have while active. That's a no-brainer to me, and I cannot fathom why it wasn't built in from the beginning... got three levels of Exhaustion? Yeah, that bonus action is really useful when you have disadvantage on all your attack rolls...

I don't agree to hit points being used as a resource in this manner, period, regardless of what value. I don't agree that the cost of the feature should be mitigated by short rests - that's too much of a benefit to an already powerful ability, the whole reason exhaustion was used was so you could not just keep using it again and again throughout the day by short resting.

You'd still be limited by how much you could rage, and there aren't infinite hit dice for short rests. 

And I don't agree that exhaustion was used for that purpose. Every other class in the game have limited resources without using exhaustion to impose the limit. They could have just made a hard cap like on bladesong, or access to progressively more uses like action surge. Exhaustion just does the same thing, but with other costs built in from beginning to end that are just annoying rather than risky. 

If you're going to replace the exhaustion it needs to be something that is equal - and a HP cost is simply not.

HP is more flexible. You can buy/craft healing potions, get it back with spell slots and items way less costly than greater restoration or a ring of spell storing. 

Also, exhaustion can mess with your hp too. Directly at 4 levels, but also indirectly by letting goblins kite you to death at the second level, or forcing you to use reckless attack constantly to lose disadvantage at the second level. This alternative at least offers no hidden hp costs. 

Exhaustion as a side-effect of your basic class feature, which should be used in every combat every day, is garbage. And it punishes your party almost as much as it punishes you, so it's basically a trap for setting up conflicts. As you've said, if the intent was to give the Berserker only one use of it per day... then like every other subclass with a limited feature, it should have been provided as a "Once per long rest..." ability. 

Burning HP to fuel damage is a good concept. It would dovetail nicely with Rage Beyond Death, too bad that's in a different subclass... but if you're rewriting the subclass, nothing stopping you from doing it top to bottom (the Berserker's 6 is outright useless and offensive, and the 14 is meh at best and should be reworked). It feels thematically similar to Reckless Attack, another way that Barbarians have to essentially use their hit points as a resource to fuel offense. I'm not sure that I would agree wtih completely unshackling the Action economy by letting them do it any number of times in a round... too many unintended interactions, and too likely to result in the Berserker again making themself an out-of-character liability to the rest of their party... but I could certainly see something based on taking damage and reducing max hit points equal to character level, to unlock one Bonus Action attack, like the old Bloodhunter? A level 3 Berserker would be expected to have... 35 hit points I believe. If Rage 1 dropped that max to 32, Rage 2 dropped it to 29, and Rage 3 dropped it to 26 (HP Max loss reset on a Long Rest).... that would be fairly balanced I think! Even at level 20 (expected HP around 250-290ish) it wouldn't cut the legs out from under you to rage 6 or more times in a day, losing 20 max HP each time... but it would serve to minimize splash level shennanigans, for the same reason that OG Bloodhunters were so awkward to multiclass.

I think it's a good solution, I just wouldn't do the HP cost per attack, and wouldn't allow multiple extras per round. Invoke a Frenzied Rage at the time you rage by taking damage and reducing your max hit points by your Character Level, until you complete a Long Rest... it's even thematically the same thing that Berkserker is already communicating with its Exhaustion levels, it just ruins your party's ability to adventure and your own ability to use it multiple times in a day much less.

I'm stealing this :) 

Quote from Sigred >>

I agree with CM: exhaustion is important.

I go the other way, from you, on my thoughts of how to improve Frenzy--make it worth racking up exhaustion levels. One weapon attack as a bonus action? That's very easy to get from other sources. If your campaign allows feats, Polearm Master & Great Weapon Master are the two most likely candidates. Magic items are another likely source, and there's always good 'ol fashioned Two-Weapon Fighting if that's your cup of tea.

Point being, if you can reliably get a bonus action weapon attack from other sources, Frenzy is just... blah. Why bother? At bare minimum, I think Frenzy needs to provide an additional bonus to Rage Damage. That alone would make it more attractive to use even if you don't need the bonus action.

It should also allow you to ignore the effects of any levels of exhaustion you have while active. That's a no-brainer to me, and I cannot fathom why it wasn't built in from the beginning... got three levels of Exhaustion? Yeah, that bonus action is really useful when you have disadvantage on all your attack rolls...

The idea of ignoring exhaustion while in the Frenzied Rage is interesting, though it might skew things too far the other way (where you end up using it too much) though it's balanced I suppose by fully losing the ability to move and/or dying.

I don't agree though that other bonus attacks devalue Frenzied Rage; Great Weapon Master is a feat that you need to take, but a Berserker can also take it and it's actually great on them, since it means you get a bonus attack you can reliably use against mobs most turns, while saving your Frenzied Rage for the big boss that you're less likely to get a GWM bonus attack against. Plus you can use the GWM hit to damage trade in scheme on all of your Frenzied Rage attacks against a boss.

Polearm Master is a tough one to compare as the bonus action attack is weaker, so even when using Frenzied Rage you're still attacking with the full strength of the weapon. The reaction attack though combines really well with a polearm Berserker, especially if you play into 14th level when you get the free Riposte every turn as well, so you should be getting a reaction attack nearly every turn, and can add that on top of a full bonus action attack during a Frenzied Rage.

I have to say I agree with Cyb3rM1nd on the idea of trading off against HP; at the very least you'd have to make the HP cost scale with level as otherwise you risk making the cost even higher at lower levels, or negligible at higher ones, but I don't think there's an obvious correct place to set it. HP is also far too easily recovered compared to dropping exhaustion.

Personally I'm a fan of it being exhaustion, as it's a good fit thematically since a Berserker who's pushed themselves beyond their limit should be exhausted. If anyone really wants to make an HP based alternative it would maybe make more sense to make it cost one or more hit-point die, meaning it limits your ability to heal during short rests instead and still fits the theme to a degree, but the balance on that is tricky as a group could get most of their healing from potions and hardly ever use any hit-dice.

Quote from Sigred >>

I agree with CM: exhaustion is important.

I go the other way, from you, on my thoughts of how to improve Frenzy--make it worth racking up exhaustion levels. One weapon attack as a bonus action? That's very easy to get from other sources. If your campaign allows feats, Polearm Master & Great Weapon Master are the two most likely candidates. Magic items are another likely source, and there's always good 'ol fashioned Two-Weapon Fighting if that's your cup of tea.

Point being, if you can reliably get a bonus action weapon attack from other sources, Frenzy is just... blah. Why bother? At bare minimum, I think Frenzy needs to provide an additional bonus to Rage Damage. That alone would make it more attractive to use even if you don't need the bonus action.

It should also allow you to ignore the effects of any levels of exhaustion you have while active. That's a no-brainer to me, and I cannot fathom why it wasn't built in from the beginning... got three levels of Exhaustion? Yeah, that bonus action is really useful when you have disadvantage on all your attack rolls...

 The houserule I currently use is that Berserkers can roll a Con check at the end of their Rage to not accrue the exhaustion. I was thinking of changing it give them the first Frenzy of the day absolutely exhaustion free and only accrue Exhaustion on subsequent uses.

But I definitely agree that they should ignore the effects of Exhaustion while Frenzied.

Thats fair. Great Weapon Master and Pole Arm master are all the time things, but frenzy is designed to be limited in some form. 

Quote from IamSposta >>

The houserule I currently use is that Berserkers can roll a Con check at the end of their Rage to not accrue the exhaustion. I was thinking of changing it give them the first Frenzy of the day absolutely exhaustion free and only accrue Exhaustion on subsequent uses.

But I definitely agree that they should ignore the effects of Exhaustion while Frenzied.

What's the DC on that CON save? The problem with a CON save is that a low CON Barbarian seems rare, and they have proficiency on CON saves as standard, so they're probably on a +5 or so from 1st level, and it'll get a lot higher as time goes on. One free use per long rest or such would be the simpler option, and avoids them potentially becoming effectively immune to the penalty entirely.

Having thought about it more, full immunity to exhaustion during Rage/Frenzied Rage feels a bit strong on top of other changes. I wonder if an alternative to "immunity" might be something like:

Tireless Rage

Starting at 5th level, whenever you are raging, you treat your level of exhaustion as one lower until your Rage ends.

I purposefully made this 5th level as that's when you gain an extra attack, which changes Frenzied Rage from +100% damage to +50%. Until that point I think no "resistance" to exhaustion is necessary as it's already a lot better with a free use.

I'm not keen on the name, but the only other one I came up with was "Caffeinated Rage" which I found far more hilarious than I should, but definitely doesn't fit with a serious tweak.

Unless you’re prepared to respond to this, don’t talk to me.

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