D&D 5E Help with 5E Monster Effectiveness

[Dausuul]

1. Moar. Just throw in more of what you have. Due to bounded accuracy, numbers matter.

This is the main thing. Remember that the D&D rules do not and cannot know how skilled your particular players are. "Hard" is a generic measure meant for the "average" play group (and even by that standard, it may not live up to its billing). You will have to calibrate encounter difficulty to the skill of the players and the power of the PCs.

Are they slaughtering Hard encounters? Try Deadly. Do they mow through that too? Crank it up to Deadly plus 50%. Keep going until you reach the desired difficulty.

 

[S'mon]

Why are you using such weak (CR 1/8?) monsters? Use squads of hobgoblins with Martial Advantage (and a leader giving +d4 on every attack), gangs of Thugs with Pack Tactics, that sort of thing. Maybe some Veterans backed up by an Assassin...

 

[FormerlyHemlock]

First level Faerie Fire can help overcome high AC characters. Fog Cloud can force ranged PCs to get closer to the fighting. Web is 2nd level. Slow and Hypnotic Pattern are 3rd. Either of those will wreck the PCs if there are weaker enemies to take advantage of the chaos and keep the party from striking the caster. Hold Person and Heat Metal, both 2nd level, can make the front line collapse in moments. Bless and Bane, both first level, will help allies or weaken enemies. Moonbeam and Flaming Sphere can shut down portions of the battlefield. Spells of level 1-3 are generally found on the spell lists of CR 2 creatures, and you can freely substitute spells known without changing CR.

I've mentioned this before, but there's a cruel part of me that really wants to put some PCs up against six Magma Mephits and a couple of werewolves. It's only officially a Medium fight for 4 7th level characters, but... "Have fun fighting the werewolves without any magic/silver weapons, kids!"

 

[JohnLynch]

3. Intelligent combat. Ambush. Surprise. Maximize special abilities. Target the weakest PC. Concentrate firepower early. Use terrain. Hit & run. Ranged from cover, then melee.

I ran an adventure the other day and the combats only featured kobolds. It began with the players on a merchant's train going along a road in a forest. One player's passive perception was high enough to see kobolds along the side of the road. They were able to give a warning shout in time for the wagon train to stop just in time to avoid having the lead horse be crushed between two tree trunks that swung down from either side of the road (think Ewoks destroying the walker). 8 kobolds then came streaming out of the path with four of them holding hand crossbows aimed at the PCs with readied actions. Alas there were 5 players and so one of the players could get spells cast and another player attacked but was missed with the readied crossbow. Alas the player's weapons were peacebound and it's illegal in this kingdom to bear an unbound weapon (even in self defence). So the casters cast spells while the others grappled. This wasn't enough to stop the kobolds from getting away with four jars from the merchant's wagon and get away (three of the kobolds were captured as prisoners). Had the players pursued the kobolds they would have faced pit traps that the kobolds carefully avoided but the PCs would have blundered into had they chased after without being very careful in where they stood.

At the kobolds lair I had kobolds standing on the opposite side of a hidden pittrap. The hall was 10 feet wide and there was a corridor on either side of the kobolds. The kobolds standing in harms way had hand crossbows. The kobolds in the wing were using their turns and actions to reload the hand crossbows that were then handed to the two kobolds in harms way. In this way no actions were wasted and the kobolds could attack with superior weapons. With this setup 6 kobolds were enough to give the players pause and find an interesting (non-combat) solution on dealing with the kobolds.

Had the players pursued the kobolds (once getting onto the other side of the pit) they would have faced 5 foot wide hallways with 2 and a half foot tall tunnels leading to other chambers that would have allowed the rest of the kobolds (12 kobolds in total) to harry the players while remaining in complete cover.

Use sufficient tactics and any creature can be dangerous (I play kobolds as very confident and dangerous when you're fighting on their terms. Completely weak and hopeless and prone to fleeing when you're fighting in unprepared terrain).

 

[Grakarg]

You can also give your monsters some class levels if it feels appropriate.
Maybe those hobgoblins are veterans of the Darkshadow war and have a couple of fighter levels.
Maybe those orcs are veterans of the Elven purge of 687 and have a couple barbarian levels.
There is some guidance for this in the DMG as well and it can really spice up a combat when the 'standard' monsters start busting out some different abilities.
Or just bump their main combat stat str/dex up a bonus and add a few more HP. Just a little tweak can have a big impact.

It does require some additional prep time, so don't overdo it as you'll spend too much time writing up monsters. I prefer to just grab and go from the MM for most things.

 

[Psikerlord#]

Yeah I think the standard healing rules and standard CR recommendations - esp if you are using feats - results in very easy combats. Other posters have really said most of it all already, but I would reiterate:

1. Add more monsters
2. Use more powerful monsters
3. Don't use the standard healing rules. Use slow healing and also consider some kind of injury rules.

 

[Rhenny]

During the playtest I monkeyed around with adding classes to normal orcs, gnolls, hobgoblins. Just a few levels of fighter, wizard and/or cleric really transformed the monsters and it was pretty easy just to add up, 2nd wind, action surge or appropriate spells.

Also, don't underestimate use of shield spells and counterspell. Counterspell especially makes it harder for PC casters.

I dig all the advice others gave too!

 

[Sword of Spirit]

Lots of good advice. My two thoughts:

1. You should almost never set up a fight with less monsters than PCs (unless you want it to pretty easy). Throw in mooks if necessary, just make sure the PCs have a hard time ganging up, or they will destroy almost anything you throw at them.
2. Read the fluff in the Monster Manual. The designers obviously intended monsters to be played deviously. I'm on my second read through and I just finished harpy. They like to use their luring song to get travelers who can't even see them to run their direction, and then fall off cliffs, into quicksand, etc. Also, the way the ability is described, if you succeed on the save against one particular harpy, you still have to make your save against every other harpy singing. And harpies traditionally hang out in groups. Half a dozen hidden harpies on the far side of a pit trap or cliff could be a TPK. Kobolds are another great example. "A trip wire might connect to a spring-loaded trap that hurls clay pots filled with flesh-eating green slime or flings crates of venomous giant centipedes at intruders." Multiple giant centipedes and green slime before the party even knows the kobolds are there waiting to pounce on their sorry, weaponless, paralyzed forms? Nasty.

 

[hejtmane]

Also the fun thing is to pick monster resistance to damage the players use, Trolls regenerate, constructs heal to lighting damage those are fun. Make sure to give the players descriptions of the monsters but do not tell them what they are fighting this also helps sometimes they still guess correctly but hey every bit helps.

 

[ExploderWizard]

Just leave the regular opponents rather weak and add 1 tarrasque to each combat. Things will get tougher pretty quick.