Reducing enemy HP by half to speed up combat

Question

Lately, I've been feeling like combats in my 5e game have been taking too many rounds. Once the novelty of the situation is established, the fight eventually becomes a slog as the players grind away at the enemies' HP.

For example, the party (a rogue, a paladin, a warlock, and a sorcerer) came up against two champions and a wizard. They took out the wizard quickly, and then it was just a slugfest until the champions went down.

I could end some fights early by having monsters flee or surrender, but I've been thinking about simply cutting the HP of their enemies in half to make these fights go faster. I'm also considering increasing the enemies' damage output to balance the reduction in CR. Does anyone have experience in reducing enemy HP totals? Did it appreciably speed up your fights? Does it totally screw up the balance of the game?

I'd like to emphasize that I'm trying to reduce the total number of rounds in a combat, not the time that any individual round takes. Additionally, I'm not changing the PCs' HP, only the monsters', unless an answer thinks that that's also a good idea.

@ClearlyToughpick That's a frame challenge, and is acceptable if the answer can be made to address the question—i.e. What are the risks in reducing the total number of rounds in a combat by making it so the opposition deals more damage but dies more easily? may not be answered by Narrate the result when the outcome is certain as that may not reduce the rounds of combat and, instead, just changes what they look like! You can totally give it a shot, though; if it doesn't help the asker, it may still help others. — Hey I Can Chan, Mar 04 '17 at 10:08

score 7 · Answer 1 · edited Apr 13 '17 at 12:45

This problem will not be solved, but new ones will arise

Two of my DMs tried halving monster HP and doubling their damage, but we soon returned to the original values.

General consequences

The results of the fights will be more swingy, if the party wins the initiative, they might wipe out the monsters before they are even damaged. If they are surprised however, it might result in a TPK.

Side effects
The Alert feat is far more valuable than before.

Reasons of slowness

There might be three reasons every fight takes to long:

Slow decisionmaking (the encounters actually last around 4 rounds, but takes hours in real time)
No optimization (Wizard with Cha and Con as highest attributes, Barbarian wielding a dagger and a shield)*
Optimization for defense (Barbarian with Con and Dex as highest attributes, Fighter with 3 Resilient feats at level 8)*

Effects of halving HP, doubling damage

Slow decisionmaking
As I mentioned above, the stakes are higher now, so decisions take even longer.

No optimization
The first Deadly entounter that surprises the party will kill everyone.

Optimization for defense
Your proposal is a good solution, but only temporarily. They have a low damage output, so halving the monster HP will be a visible change for them. They can take punishment, so they will survive the surprise round. Unfortunately the change will just push them further in this direction, in a few levels, the combat will slow down again.

What to do instead

This again depends on the reason of slowness:

If the party is slow, introduce a timer. A designated player handles the hourglass, or a smartphone with a timer app. Just pick a player who will not start playing with it. For us 10 seconds worked great.
If the party is unoptimized, halve monster HP without changing anything else. Now the combats finish faster without they being killed every second time.
If the party optimizes for defense, halve monster HP without changing anything else. Now the combats finish faster without the party being motivated to improve defenses even further.

*I have actually met these characters

I think I'm missing something: OP says nothing about halving the PCs' HP, just the enemies'. Your answer seems predicated on the idea that all combatants will have halved HP. — nitsua60, Mar 04 '17 at 16:45
@nitsua60, OP talks about increasing monster damage to compensate HP halving, I assumed double damage. It is about the same as halving party HP. — András, Mar 04 '17 at 17:07
The original question was actually halving monster HP, with doubling damage as a possibility. Have you tried sessions with half HP? Were they just too easy? — Icyfire, Mar 04 '17 at 20:03
By the resilient feats, you mean that they took the resilient feat three times? I recall somewhere that only the elemental adept feat could be taken more than once, as it had a clause for such a case. I believe the is a question on the site about it. — Javelin, Mar 04 '17 at 22:58

score 4 · Accepted Answer · edited Apr 13 '17 at 12:45

Yes, it will speed up combat, for the worse

With your party composition, and expecting high burst damage from the Paladin and Sorcerer, it will essentially make your game a game of rocket tag- he who wins initiative, wins the fight. As someone who is DMing a game of "all-PCs-are-casters", I have some experience of how scary this kind of game is. My PCs need to win initiative, otherwise, they need to bust out all their big spells not to die. This sorta thing makes my job easier- if my goal was a TPK, and not for my friends to have fun.

If you're going to halve enemy HP and not touch PC HP values, then you're going to get uninteresting, unchallenging combats. It won't be rocket tag anymore, the PCs just win. Without the HP to take at least some damage, creatures just can't survive long enough to make meaningful attacks against the PCs, and what's even worse is that your combats will become even more of a slugfest, as taking Actions that are not to attack or to cast a damaging spell becomes gravely sub-optimal- suddenly, taking a round to cast Invisibility results in all your other friends dying.

Try doing these instead

If it becomes clear that the NPCs cannot win, and there is no more risk involved in the combat, just narrate the PC's victory, "You back the last goblin into a corner, and after a few more strikes, it falls lifeless unto the ground". "The Champion looks harried and winded, but still determined. Working together to surround and overwhelm him, he swings his greatsword around weakly for a few more moments before you put him out of his misery."
(WARNING! AngryGM link) Manage combat like a dolphin. Alternate between mechanical effects (rolling dice, crunching numbers), and describing what it looks like in-game. If you're not already a fan of critical role, I suggest you watch this fight between their Barbarian and another Half-Orc Barbarian. Their DM does an excellent job at making what would otherwise be a slugfest, into an entertaining spectacle.
Improve your creature choices. Generally, creatures that just attack are boring. These creatures have their uses, but when building a combat encounter, keep a creature's abilities in mind and imagine it in your head what the fight will look like. Alternatively, you could have given the Champions a magic item or two just to spice things up.
Mix things up in combat - give your players more choices than just to attack. Remember, any creature can use the Help Action, Disarm, Trip, Grapple or Shove; does the paladin attack with his non-magical weapon, or provoke an opportunity attack to try to get his sword that's on the ground 10 feet away from him?

Jared Kossler · Answer 3 · 2017-03-06T06:04:49.447

4th Edition did it.

In forth edition they had minion creatures that had one hp. These creatures were meant to be weak creature that while could get a hit off and reduce party resources, they would be killed in a single hit. This made it so you could have a decent scale of battle with out a lot of tracking or time consuming grinding down the baddies.

Matthew Colville has a YouTube video going into detail on how to use such a method in 5e. The video is called Using 4E to make 5E Combat more fun! Running the Game #31. He discusses minions in min 9:10 to min 12.

In this video he discusses how action economy is very important in this edition, and how minions allows you to balance it better. He also is able to do this from a point of experience.

His example was that he wanted to prevent the players from killing off a boss monster too quickly. He does this by adding minions to balance action economy in the bosses favor without adding significant difficulty.

He doesn't mention this, but there isn't any reason this shouldn't work in reverse. This can be done by replacing a few monsters with minions and add a couple more to keep a good CR rating and the fight will end sooner.

Though admittedly I do not have any experience yet with this method. I just thought this was worth a mention if you find no better suggestions.

I added my experience but I dont think it improves it much. I did refer to a YouTube video that has a few valid comments on the idea. I don't know if that is OK on this forum but if it isn't, I may just delete the answer. — Jared Kossler, Mar 05 '17 at 17:36
Citing someone else's experience is valid here, yes. Adding a summary of what Colville says the benefits are (i.e., his experience with how it changes combat) would be one way to improve it further though. — SevenSidedDie, Mar 05 '17 at 21:28

score 0 · Answer 4 · answered Mar 04 '17 at 13:34

Yes,

I'm currently DM'ing and for any modifications to monster HP or damage output, I use the tool

Quick Monster CR Calculator

It is a wonderful tool, but I'm not a 100% sure if this is for 5e. Yet it is pretty handy for doing what you are suggesting: reducing monster HP to speed up combat. With this you can increase their damage output (or AC, bonus to attack rolls or spell save DC) to ensure the monsters CR stays the same. It does speed up combat, but I would suggest reducing HP 20-40% max and increasing damage output accordingly, to make sure you maintain balance.

Word to the wise, turning monsters into "glass cannons" puts a lot of strain onto your players to roll high, since a few botched rolls from them and a few successes from you (the DM) could result in a party whipe in no time.