How do I kill a 20th level raging Zealot Barbarian?

Question

At 20th level, the Path of the Zealot barbarian (Xanathar's Guide to Everything, p. 11) can rage indefinitely by virtue of starting a new rage just prior to their initial rage ending. This is confirmed by this question: Can I start a new rage before the previous one ends?

At 14th level, they also picked up the Rage Beyond Death feature, which lets them stay active at 0 hit points and regardless of how many death saves they've failed:

While you’re raging, having 0 hit points doesn’t knock you unconscious. You still must make death saving throws, and you suffer the normal effects of taking damage while at 0 hit points. However, if you would die due to failing death saving throws, you don’t die until your rage ends, and you die then only if you still have 0 hit points.

At 15th level, barbarians gain the Persistent Rage feature, meaning their rage ends only if they fall unconscious or choose to end it.

Given that the Barbarian can constantly remain in a state of rage, how can I ever reliably kill them?
"Reliably" meaning they won't get a save to negate the effect, since they would be able to constantly cycle their Fanatical Focus feature to ensure rerolls on saves.

Answer 1

Brute force won't work, but any other effect will work, provided it is hit point-dependent

At first blush, the 20th level Zealot Barbarian seems unkillable, and this is true if you play the Barbarian's game by engaging them in direct melee combat. Indeed, by RAW the Barbarian could massacre an entire army of mundane soldiers and continuously maintain their rage until they were able to find any sort of healing to recover the minimum 1 hit point necessary for them to keep on trucking.

However, 5e has a handful magical effects that can be used to reliably handle this situation, though.

• Sleep: It's only a 1st level spell, but if you can reduce the Zealot's hit points enough (or upcast the spell high enough), you can forcibly end the rage by knocking them unconscious. If you do this when the Zealot is at 0 hit points and has failed 3 death saves, they will die on the spot.
• Power word kill: If you can get the Zealot below 100 hit points, you have the option to drop them outright with this.

This is a fairly short list that curiously hits both ends of the spellcasting spectrum, but either will stop the Zealot on the spot.

There are a few other options accessed by turning into a creature with true polymorph or some other method to access them. These all require you to reduce the Zealot to 0 hit points, be aware that it can be difficult to do this because the Zealot can make several saves due to Relentless Rage to instead be reduced to just 1 hit point:

• Shadow Dragon's Shadow Breath (MM, p. 85) will instantly kill a creature reduced to 0 hit points by this attack.
• Mind Flayer's Extract Brain (MM, p. 222) will instantly kill a creature reduced to 0 hit points by this attack.
• Phase Spider's bite attack will paralyze a creature for 1 hour if the poison reduces them to 0 hit points, which means that the rage will lapse after 1 minute and the Zealot will die.
• Swarm of Centipedes' bite attack (MM, p. 338) will paralyze a creature for 1 hour if the poison reduces them to 0 hit points, which means that the rage will lapse after 1 minute and the Zealot will die.

These methods are most viable after you've reduced the Zealot to 0 hit points since you won't trigger their Relentless Rage, which the Zealot can probably reliably make 2-3 times before it starts getting tricky. I've avoided effects that rely on trying to reduce the Zealot's maximum hit points to 0. While they technically would work, you would find yourself spending an absurd number of rounds trying to reduce a feasible 275 maximum hit points.

One last method that would reliably work is:

• Forcecage: Trapping the Zealot in creates a situation whereby you can plink down the Barbarian's hit points and implement any of the other strategies.

Answer 2

I agree with Pyrotechnical's comprehensive answer, but I think he missed a few spells:

• Plane shift (CHA save) to the Abyss, the Plane of Fire, or some other inhospitable plane on a non spellcaster is an agonizing certain death warrant. (But not, sigh a surefire death warrant.)
• Polymorph (WIS save) disables class features (like rage), ending the rage, which allows you to then cancel your concentration and kill the barbarian.
• Disintegrate (DEX save kills creatures if they are reduced to 0 HP.
• You can possibly stop rage with command ("chill" or "stop" or "halt" ); suggestion might work as well, as does mass suggestion. (WIS save) But this depends on the DM, as all of these spells don't allow you to give a command that would directly injure the creature, and ending the rage could be construed as directly harming it.
• Banishment (CHA save) incapacitates the target for a minute, ending rage. Also sends them to another plane out of your reach.
• Hypnotic pattern (WIS save) incapacitates for a minute, again ending the rage. Ends early if the barbarian is damaged.
• Hold person (WIS save) can potentially work as well, but it seldom lasts long enough, and so it's probably not worth using; the same applies to hold monster.
• Dominate person (WIS save) works in a similar vein to suggestion and command, but also allows you to use the weak-minded barbarian as your slave, for a short duration.

Answer 3

Ability Score damage.

Drain their Int scores with Intellect Devourers (MM 191) (enough of them are a threat to a Lv 20 due to bounded accuracy.) Their Devour Intellect power will drop Int to 0 immediately. When the Barbarian hits 0 Int they are stunned. Bye bye rage actions.

With the Shadow, (MM 269) their Strength Drain can whittle down the Barbarian's Strength 1d4 at a time until they die at 0 strength. It would take a lot of them, but once again, bounded accuracy makes it doable.

Answer 4

While the character described can endlessly rage, the character is still vulnerable to the effects of exhaustion due to lack of sleep. As they miss sleep periods (I think it is safe to say they can't rage while asleep!) they will accumulate exhaustion points, or if that rule is not being used then common sense says at some point they just cannot continue to stay awake, as adjudicated by the DM.

When asleep they cease to rage and they can be killed if enough damage is done before they awake and rage again.

However a race that does not suffer exhaustion due to lack of sleep (e.g. warforged) would not suffer this issue.

Answer 5

Deal damage equal to their max hit points.

Massive damage can kill you instantly. When damage reduces you to 0 hit points and there is damage remaining, you die if the remaining damage equals or exceeds your hit point maximum.

Damage at 0 Hit Points. If you take any damage while you have 0 hit points, you suffer a death saving throw failure. If the damage is from a critical hit, you suffer two failures instead. If the damage equals or exceeds your hit point maximum, you suffer instant death.

—Death Saving Throws, Player's Handbook, pg. 197

The crucial line from your quote is:

if you would die due to failing death saving throws.

In the case bolded above, it's not a saving throw, so they are pulverised.

Now, how you deal that much damage to a raging barbarian is another problem.

Answer 6

Persistent Rage only prevents the rage from ending early, meaning the barbarian's rage still ends after 1 minute, and if they have failed 3 death saves they will still die.

Since a minute is 10 turns of combat, it could just last that long.

Also, starting a new rage takes 2 bonus actions, meaning you are down a rage for a full round: "You can also end your rage on your turn as a bonus action." And if they have 3 failed death saves, they die the moment they try this.

Answer 7

You...punch him.

Seriously. You punch him. The reason is because the Zealot is immune to death, but not being unconscious. And as per the Knock a Creature Out (KO) rules:

When an attacker reduces a creature to 0 hit points with a melee attack, the attacker can knock the creature out. The attacker can make this choice the instant the damage is dealt. The creature falls unconscious and is stable.

While the Zealot does have the ability to ignore being knocked unconscious from normally hitting 0 HP, the KO rules imply to bypass those rules completely. Rather, making the creature unconscious is part of the trigger for reducing the creature down to 0 HP, otherwise it wouldn't be stated with the other exception of "the creature [..] is stable". Both are applied from the KO rules.

So you punch him. The side effect of this is, since your attack doesn't cause the Zealot to start dying, he's stable regardless of the number of Death Saving Throw failures he had and will need to be finished off.