How do I pick monsters of appropriate CR for parties with superior armour?

Question

As background, my low-level PCs managed to come into a "king's ransom's" worth of cash (due to poor planning on my part as DM, I'll admit) and now have purchased armour/enchantments that give them higher AC than would be normal for characters of their level.

Now, when I throw monsters with challenge ratings equivalent to their party's level, they do not pose any serious threat. I want to know, aside from trial and error, what methods there are to calculate the appropriate monster challenge ratings to throw at them? Note that their ability to hit is still low and I am trying to avoid a TPK ...

I am trying to work with something the players are stoked about, as opposed to just taking it away for the sake of correcting my own mistake :) I have considered the use of monsters that work with touch attacks instead.

Answer 1

Use two-part encounters: opponents that the armour is effective against, plus opponents that care less about the armour.

For example, a necromancer who has a host of skeletons raised will challenge a group in different ways. The skeletons will be fun to smash through with impunity, "challenging" the armour and giving them the satisfaction of seeing it do its job. The necromancer will be using spells that challenge the party's saving throws, giving them a real problem that they can't just ignore behind a wall of armour.

The trick is to find the CR of the "mob" creatures and the CR of the "real challenge" creature that will actually be fun without being overwhelming. The skeletons in the example won't be much of a challenge, but spells can tip the balance and make a character suddenly vulnerable. Similarly, the necromancer in the example can't be high enough CR to challenge the party all by themselves since the skeletons will be absorbing attacks and constraining the PCs movements.

It can make for a very swingy fight, so start small and pitch the CR of the two parts low. Don't be bothered if one or the other part gets taken out quickly – the players will enjoy the halfway success and they should reap the benefit of making the other opponent easier by taking out their support. Getting a feel for this kind of encounter will take some time, because it's outside of the "level-appropriate encounter" design paradigm. Besides, the first time the players get into this kind of encounter they're likely to underestimate the challenge. They will notice even a weak challenge that can get around their armour, and they won't underestimate that next time.

The important thing is to keep challenging the armour. The players have spoken, and they want to see things smash to bits against their superior defenses. If that's all you had happen it would get boring fast, but it will remain satisfying for a long time if they can enjoy that smashing as a background to other, still-challenging action.

Answer 2

Apart from upping the monster level there are several others ways you can handle it; not all encounter based:

1. Wind back the clock; tell the players what the problem is, explain that the back story has left a big problem and that it risks them fighting stuff that will TPK them; work out some other rewards from their back stories (allies that will get them said items later on maybe) and then go back.

2. Remove the problem; as mentioned above use monsters like rust monsters; people who demand tolls or bribery, or thieves to steal their gear - low level adventurers with valuable stuff are a prime target to get their gear stolen - stick them in a situation stripped to their underwear and make them fight to get that gear back - by which time their success should have upped their level to where they'd have the gear they started with.

3. TPK, if 1) didn't work use monsters that CAN hit them and let them see just what problems they're going to have. Note this is an option, but I don't really approve of it.

4. Work monsters smarter; give the monsters gear or tactics to deal with their parties advantages. Dump them in lakes (keeping that armour on now?) glue them to the floor, cover them in acid (it burns, get that armour off!) or mass disenchantments from magi to deal with problem items. Pick monsters that can get around their defences (like touch attacks as you mentioned) area effect weapons, breath weapons, choking gas, grapple attacks, spells, there are many ways to attack a player and AC is just one of these; put them through traps like falling blocks that play off their stats to weaken or scare them; they may have a feeling on invulnerability from their gear and you need to shake them a little out of this comfort zone and get them worried again.

5. Creep up the CR encounter after encounter to test the waters to see what they can deal with, push up existing monsters so they have more hits to last longer or better attack to deal with the problem; chuck in more boss mobs surrounded by minions they can hit to make sure they don't get disheartened. You can also scare them with a REALLY badass monster, something that does wipe the floor with them, this monster can then get beaten back by a savior of some kind and flee (vows to come back or escapes to it's lair) the party will probably want revenge, the savior can help them find item X, spell Y, secret trap Z that can help them get their own back.

6. The final DM clause. Cheat ;) The party is probably feeling pretty comfortable in their super-expensive layers of protection; what they need instilled back at them is a sense of danger; give monsters nice one-shots (ie ooo that hit, yep yep yep) that allow them to start an encounter off with a dangerous attack to shake them into thinking it's a worse fight than it is; if your monsters are getting minced then change their stats during the fight if you need to challenge them, that monster did have an extra 20 hits didn't it? If a fight has been a breeze for them let the monsters get in a couple of "lucky" hits to shake the players towards the end, just a bit of damage here and there can make the players more worried and make the encounters more exciting. You have that control.

Answer 3

I think taking the armor from the characters is a bad idea. It creates resentment (I have been there myself and quickly found out heavy handed tactics or railroading is a option of last resort).

However instead of simply uping the CR monsters the party faces. Take some time to start crafting some fights that partially or fully negate the armor bonus (slow, back stab, underwater, mud, climbing etc.. etc..). Another all around tool of the DM is Dispel Magic which most of the times will negate all those pretty enchantments. Other spells that with some work can be quite effective is Grease, Slow, Heat Metal, Feather Fall (no one expects crossbow wielding Goblin paratroopers), Suggestion etc.. etc.. Look for the lesser known spells so the PCs will know be as well prepared.

If that fails then you could always come up with ways for them to part with their new found wealth such as convince them the person that sold them the armor was arrested for putting hidden curses on the items that cause the wearer to do his/her bidding. Then have a thief sneak into the camp and put some random items in the camp to make it look as those one or all the party has been doing something in their sleep (or some variation of this theme).

Answer 4

I'm not sure why making the armor ineffective is really preferable to taking it away - it amounts to the same thing and the players will probably realize what you are doing.

I would probably give the players a choice about what CR they want to take on. They could either mow down most of their opponents at standard CRs, or they could go over CR a bit and level up quickly (I would look for an excuse to level them quickly in any case because it might get boring until they do level up a bit if they stay at normal CR encounters).

I would try to make a little bit of a big deal in-game about going after higher CR encounters ("this is a difficult task for one so young" kind of thing) to emphasize to the players that they are ahead of the game.

If you have a realistic and/or difficult type of campaign, I do think it's reasonable that characters walking around with really valuable stuff, that they are much less capable of protecting than the people who usually have that kind of stuff, might be a target. I wouldn't by any means have some deus ex machina beat them up and take their stuff away, but if they let it be known that they are rich and not that powerful I might hit them with a very tough fight against people trying to rob them, or some kind of thievery attempt, swindle, or scheme.

Answer 5

I completely agree with psr about giving your players a choice. If they want to just "mow down" weaker opponents, let them. The game is about the players, after all. But taking on something tougher should be presented in such a way that it seems like the more exciting choice.

Regardless, if you somehow take away/negate the cool stuff the PCs feel like they earned, they'll resent it and be less excited about the game going forward.

I would also recommend that the next tasks you present to them are low/no reward right out of the gate. The old woman says she can offer nothing in the way of a reward for the PCs' help, but she would be grateful, has no one else to turn to, etc. If the PCs agree to take on a few low-reward adventures, it'll balance out eventually. Let their reward be "doing the right thing" for a while. Maybe give them favor or some healing potions. The point is, don't exacerbate the problem by dumping even more gold on them. And if you point out the lack of/low reward at the time you present the task, there won't be disappointment when the PCs complete it.

There's a great conversation here on stack exchange about non-magical rewards. It doesn't exactly apply to what you're talking about, but there are a lot of great ideas for non-monetary/non-magical rewards you could confer to your characters until they level to a point that their new awesome armor makes more sense.

Good luck

Answer 6

It depends on the "flavor" of your world. The big question is Just how common is magic? If magic items of this caliber are relatively commonplace then you should be handing similar items to your monsters (thus upping, perhaps, their ability to hit).

If magic is more scarce (which, given the "DM error" statement above, I'm assuming) then I'd second the "tough fight against people trying to rob them", but I'd take it even further.

In this case, as described, your PCs would stick out as easy marks. Just as they'd travel miles and miles for adventure, there would be thieves that would travel miles and miles for an easy mark! Even if they repel the attacks repeatedly, the casters are going to get tired of losing their much needed sleep ... and the thieves KNOW this.

Make sure you have your attackers retreat and heal (I know ... the withdraw rules in 3.5 kinda suck). They know they can disable the casters by attacking, waking them up, and leaving repeatedly through the night. After a time of being harried by this your PCs may want to set aside the armor on their own to keep from attracting attention.