Adjusting to Tier 3: What to do, and what not to do

[Nagog]

Howdy!

So I'm DMing for a party that's just reached level 10, and entered into the realm of Tier 3. I have a lot (a few years) experience DMing and playing in Tier 1 and 2, but very little experience at anything beyond level 10. My party is generally RP focused, but there is one minmaxer (a Hexadin) and a heavy utility Cleric (Life domain), and when the Hexadin is capable of dealing 60+ damage per round and the Cleric has a great deal of Divination/Social issue problem solving spells prepared each day, I'm struggling to give them a real challenge. What are some ways to adjust enemies, encounters, or other game effects to compensate? I'd like to keep the promise I made saying we'd reach max level (probably not until right before the final session), but I'm already struggling to challenge this party here. What adjustments should I make to my style to keep things interesting?

[Amnestic]

What adjustments should I make to my style to keep things interesting?

How much are you specifically targeting characters weaknesses in combat? Hexadin does a lot of damage, but he's not good at everything (...probably). By the time they're level 10-11 they should be famous throughout the country they're operating in, maybe even world famous depending on the setting. Enemies should have decent ideas ahead of time of what each party member can do and tailor their response accordingly. I wouldn't treat them as having perfect information - they shouldn't be fully aware of everything - but if they stick to some 'staple spells' in combat or common tactics then respond accordingly. Spreading out from AoEs, forcing the hexadin to fight at range instead of in melee, targeting weak saves or low AC/HP characters, focus firing one target. A paladn's aura is only 10' at the moment, which means he's probably not covering the whole party. An upcast Hold Person has a decent chance of ensnaring at least a couple of them for a round or two and makes them a lot more vulnerable while they're held.

They've got access to ample healing and a few resurrection abilities now, so murdering characters isn't the end of the world (probably).

Enemies should also be actively prepared for the party to arrive. If they're well known as do-gooders, and they're dealing with high level threats, those divination spells work just as well the other way. Traps should be set up not for "quiet dungeon hallways" but as combat mechanics to be weaved in. Caltrops scattered liberally, trip wires, pitfalls, all of these can turn a fairly bog standard encounter into a slog.

Might need more specifics if you want more specifics. What's a typical 'adventuring day' for them? Do they do intense back-to-back fights dungeon crawl style or is it sparsely placed? What's the last fight that they had that you thought was 'too easy' for them?

[Chronic]

It's time for them to face casters with real, efficient spell list (heavy cc and such). It's time for them to get scried on and researched regularly by badguys, justifying counters to their usual strategies.
Also don't hesitate to use expensive spells for bad guys, they have only one life and you can't spend your gold when your dead.
This is tier 3, opponents are usually smart and cunning.

[Ashrym]

Stretch out longer adventuring days with more encounters. Based on the classes you mentioned they seem to be replenishing resources too easily.

[MrStabby]

Tier 3 is where the gloves come off. This is where the party no longer faces of against threats that are not smart, that dont prepare or are just not fit to survive.

Mooks are expendable and they should be expended to drain resources. Spell slots, per rest abilities etc.. And the serious threats should scary.on the party to hit them when they rest to recover. The higher level you get the greater the disparity between a party with resources and a party without. The bad guys should be taking the initiative and attacking rather than the PCs being able to say "OK now let's open that next door, I still have some spells left and armour of Agathys hasn't run out".

I find at T3 pretty much all your enemies should have access to at least a couple of low level spells. Shield and Misty Step become almost mandatory - even as just a once per day ability each.

Use your illusions - misdirection and get the PCs to waste resources or reveal themselves prematurely. Programmed illusions can be great for this.

Use big spells unapologetically. Heal that giant. Feeblemind the cleric. It's not unfair by mid T3, the PCs have classes with access to divination magic and protective effects. If they dont use them it's their fault.

Use combinations of spells and abilities. Use poison immune enemies with sentinel effects with cloud kill spells. Even mundane things like caltrops with spells where you want the PCs pinned in place can be brutal.

Ok, some of this depends on your table and your attitude but I find that T3 is fun when players are.more scared about what's coming after them than they are confident because of their newfound abilities. You want to make them value their newest most powerful abilities, not because they crush the enemy, but because the party would be dead without them.

PCs that can use all their resources offensively are exceptionally powerful. Diversify your threats and make the requirements for utility spells such that even at this level you put pressure on their spells known/prepared. When you need dispel magic, remove curse, raise dead, restoration and so on it can narrow what you have left (ok, poor example with a life cleric due to awesome domain spells but a more general principle).

If a challenge is fun you really need to ratchet things up at these levels. Where a single spell or ability can trivialise an encounter you need a campaign where the main encounters wont be managed this way and where there will be enough challenge left when some of them are. You are not looking to neuter your players, just ensure the challenges are appropriate.

And keep enemies smart. If the party separates enemies with a wall of force then they retreat where they can. If the party buffs up with 1 min duration spells then the enemy can pull back till they expire. Detect magic and identify magic are only level 1 spells; at this level not making stupid life choices shouldn't be too hard for hostile NPCs.

Likewise bad guys should be smart at the planning level. If you have a stronghold, cast forbidance in sensitive areas. Locks are cheap(ish) so put a couple of them on important doors. Have traps that dont drop rocks on you when you try and open the door in front of it, have them drop in the alcove where people would try and shelter whilst poking open the door with a long pole or mage hand.

Play up the enemies. The PCs are big league heroes now. They deserve to know they are doing big league hero things. More named enemies. More enemies of repute with serious backstories. Bigger positive consequences for success. Bigger treasure!

Above all, everyone have fun. T3 is a blast - it gets a bit silly at the higher levels (actually it starts silly and then gets sillier), but the new sense of scope and scale is great both as a player and as a DM. You up the stakes, up the difficulty, and accept you can run a more complex game as everyone should know their characters by now.

[Tanarii]

Might need more specifics if you want more specifics. What's a typical 'adventuring day' for them? Do they do intense back-to-back fights dungeon crawl style or is it sparsely placed? What's the last fight that they had that you thought was 'too easy' for them?Thats what I'm wondering too.

Also for any given encounter they facing 1-2 high CR enemies, or 7+ lower? Or even 12+?

[Pex]

Be mindful with all this advice you don't go overboard. Every character has weaknesses, but it's no fun for a player to sit there doing nothing for the real world hour it takes to run the combat because a bad guy took his character out of the combat somehow in round 1 or otherwise cannot participate. Don't start killing a PC every game session just because they have Raise Dead available. PCs have Cool Things. They're still supposed to use them. They're still supposed to work. Don't counter everything they can do all the time every time every combat. Bad guys are not always omniscient. They don't always know what the PCs can do.

[Eriol]

Be mindful with all this advice you don't go overboard. Every character has weaknesses, but it's no fun for a player to sit there doing nothing for the real world hour it takes to run the combat because a bad guy took his character out of the combat somehow in round 1 or otherwise cannot participate. Don't start killing a PC every game session just because they have Raise Dead available. PCs have Cool Things. They're still supposed to use them. They're still supposed to work. Don't counter everything they can do all the time every time every combat. Bad guys are not always omniscient. They don't always know what the PCs can do.
I'm going to "yes-and" Pex here (great post man), with one more piece of advice: what do the PCs find fun? If you know what they like, lean into that. Don't just be out to kill them, find out what makes them feel awesome. Maybe yes have a "big hit" come down, and that gives the opportunity for the cleric to burn that 6th-level Heal spell to save the day. Or other things that are dangerous yes, but make the PCs feel like "ya, I prepared, and now I'm rewarded!" So instead of making cloudkill absolutely lethal, maybe drop hints from NPCs that they should spend 25g each (or whatever) on a potion of poison resistance, and then drop the big effect. Or whatever else. Or get them paranoid, and they all get cold resistance. Then make sure to use Cone of Cold on them. It'll make them feel tough!

Making things dangerous can be fun. There should feel like there's some stakes, but there are many routes to fun, focus on that.

[5eNeedsDarksun]

Stretch out longer adventuring days with more encounters. Based on the classes you mentioned they seem to be replenishing resources too easily.

Related to this I'm going to give some advise that I'm trying to follow myself. That is: be OK with your play session ending without a long rest.
At lower levels encounters are quite quick and I find it fairly easy to finish a night of play with the characters having completed 6-8 encounters (or more) and legitimately back in a place where they can recover. At higher levels encounters just take a long time to resolve as combat becomes more complicated and 1-2 combat encounters + whatever else you are doing might take the entire session. For me anyway I was starting to fall into a pattern of giving the characters long rests too frequently, and just having deadly encounters. Not doing this requires more record keeping, but does keep higher level characters in check and from going Nova too often.