My entire party is filled with casters.
More specifically, we have a Paladin(I suppose that's just a semi-caster), a wisdom-focused Druid, a Witch, a Kensai Magus, a Transmuter Wizard and a blastermaster dragon-disciple Sorcerer. And me as the DM.
Needless to say, battles are very flashy, and a lot of spells gets thrown around. A lot of powerful effects, and we're now getting up to a bit higher levels(level 8 at the moment), and I'm really starting to feel how problematic running encounters are for them. We're currently doing the Kingmaker adventure path, and it includes a lot of singular encounters throughout the world map. What's mostly problematic is:
The transmuter and the sorcerer isn't bad. The sorcerer deals a lot of damage with his fireballs and breath weapon, but anything from broken. The Transmuter is fond of those annoying pit-spells, which can lockout combatants for pretty much the entire combat.
The Witch, has a lot of powerful mind-effecting hexes and spells. She can essentially slumber most big monsters such as giants and the like, or illusion-trick most more mindless beasts. She also has the fortune hex, which leads on to the next point...
The Kensai Magus. It's a real monster in melee. With mirror image, the highest AC in the group, and access to greater invisibility, he's anything but a glass cannon. This magus fights with a Scimitar and always puts keen on it - resulting in massive spellstrike crits(using mostly frigid touch or shocking grasp) that range up to 50-70 damage. With the fortune hex, he'll be critting about 50% of the time, so even the toughest monsters will stand little chance, provided they aren't status-effected by the others. I suppose his damage is not sustainable in longer dungeons, but I'm not a fan of long crawls, and the adventure module doesn't have that many of them either.
How do I solve this situation the best? Some of my players feel unhappy by the fact that the Magus is doing so well, they've asked me to double-check that he's playing everything by the rules. So far I've not found anything conclusive on that part. And I'm fast becoming unhappy my encounters are becoming pushovers either by oneshotting magic spells or too much damage, and I don't think my players are feeling terribly challenged either.
My suggestion is to have less BBGs and more "mass combats" with spaced out opponents. Also try to make sure the creatures aren't Evil.
What's the point of doing 50 damage per hit if the creature only has 20 hit points, but there are 10 of them.
Hit and run tactics.
Invisiblity
Obsuring vision
Enemy parties (check out the Rivals Guide)
Add an attacking Nation
Juju zombies (neutral undead)
Rampaging/territorial animals (neutral)
I'm sure there are better explainations of how to challenge your players from other posts in this forum.
Whatever you do though make sure you and your players are having fun - its not you vs. them.
My suggestion is to have less BBGs and more "mass combats" with spaced out opponents. Also try to make sure the creatures aren't Evil.
That's not really the way the AP is written, though.
And if you're going to have to do mass surgery on the thing (even if, in some ways, Kingmaker is best suited of all the APs for it), why run an AP?
Golems are certainly a possibility, they would mess their stuff up major-league. But I can't have golems in every encounter.
More enemies are indeed better, one of the more diverse fights they've had was against a bunch of Spriggans that holed up in a castle and used blackpowder kegs to set traps for them. The battle was still a whack-a-mole as the witch dropped NPCs one by one with her slumber hex. But it's very problematic to create encounters like this, it takes a lot of time and you need to think about balance, as it can easily tip over if you're not careful.
I'm thinking I need to drop in a few more spellcasters perhaps. A wizard or cleric NPC in some of the fights could really make the fights more interesting, especially with plentiful uses of dispel magic.
I dig golems like no tomorrow, they're my favorite creatures in the game, and my players know that. Have the BBEGs protected by some golems because obviously he'll know about the party's magical abilities. Have him employ high-ish CR creatures with SR, that'll mess up their day.
Often if you just start being a stickler about the rules many casters become less powerful.
Many GM's waive fees for writing spells into spell books, some simply because they don't know they are supposed to be there. This affects wealth of the characters, also costly material components and spell foci are often over looked. In a group with one caster these sorts of concerns don't add up to much but with a group of all casters, compliance issues might bring things back into line, maybe though I doubt it if you are in the kingmaker adventure path...lots of time there. Don't forget watches, rest requirements, etc. Nighttime harassment from nightmare spells from enemies, foes that use private sanctum, why wouldn't they? Or just lead sheeting to block diviners. The AP's weren't designed for this type of lopsided party so you had to know some adjustments would be necessary. Not giving you grief, I would love to run or play in a game of all casters, I think the idea and possible synergies and challenges would be awesome. Good luck.
I'm guessing your party is at least level 10 if the magus can cast Greater Invisibility. I suggest reflecting on your parties tactics and building some encounters that slightly bypass them. Many outsiders have fire resistance, spell resistance and, more power ones, have constant See Invisibility or True Seeing. Casters, with prep time, can nullify some spells, have buffs on their party or themselves. Reflex based classes or monsters have Evasion to avoid AoE damage and effects. I'm not saying build all of your encounters against them, think of it this way: Level 10+ characters also build up some sort of reputations or start catching the attentions of unwanted onlookers, so use some of that as reasoning to what the encounters are now countering them in some ways. Using traps in strongholds or the terrain to add some extra excitement to encounters. If you employ the pendulum style of encounters, some encounters will be a breeze while others will be grossly hard and force the party to think, research or have a bit of luck. As long as the party gets a sense of accomplishment or a nice reward to brag about, you did your job as a GM.
Throw a few golums at them. :)
3.5 and PF are crazy flush with SR: No spells which are also great enough that you'd already have them prepared anyway even if you weren't expecting golems.
Personally, I think there are too many such spells, but that's the game as written. Golems aren't any more of a threat to the Pathfinder wizard than they are to the Pathfinder fighter.
An enemy mage that had a few rounds to buff their minions before-hand because the party failed to be stealthy would make encounters more difficult.
I recall several encounters where things like Mirror Imaged mage...or pre-summoned creatures...or the Greater Invisibility cast on the Dragon.
You get the idea.
Also have the enemy USE UP magical items. Oh you just crit hit the enemy...he 5-foot steps back and drinks a potion (one less potion in the loot).
Or the enemy Dimension Doors away with one of the enemy...they heal up, and then come back.
Reocurring villians are good too, but they have to have abilities like Greater Teleport or something that prevents them from being controlled by the PCs (e.g. Protection from Good).
Find the types of combats your groups like to fight and custom tailor the AP to your party. The AP is an AID to you...its not written in stone. Besides one or more of your players may have already played the AP and would welcome you tweaking it a little so it feels refreshing to play.
That's my 2cp.
My entire party is filled with casters.
More specifically, we have a Paladin(I suppose that's just a semi-caster), a wisdom-focused Druid, a Witch, a Kensai Magus, a Transmuter Wizard and a blastermaster dragon-disciple Sorcerer. And me as the DM.
Needless to say, battles are very flashy, and a lot of spells gets thrown around. A lot of powerful effects, and we're now getting up to a bit higher levels(level 8 at the moment), and I'm really starting to feel how problematic running encounters are for them. We're currently doing the Kingmaker adventure path, and it includes a lot of singular encounters throughout the world map.
Part of the "problem" is that you have 6 PCs in an AP designed for 4. The party will have 50% more actions in combat and be able to deal with a wider range of circumstances. The extra actions are especially advantageous against single opponents. As a rule of thumb, a party of 6 PCs should be treated as if they are APL+1 when considering encounter difficulty (in an AP, they should be one level behind on the recommended advancement track or the GM has to increase the difficulty of the encounters).
Note that as the party finishes The Varnhold Vanishing and starts Blood for Blood, there will be more combat encounters against groups, which will limit the party's ability to effectively "gang up" on opponents. Also note that this will tend to make the blaster more effective when they're able to drop area of effect spells on their foes.
The type of opponents encountered as the campaign progresses will also change, which will allow different PCs to shine and/or be less effective in that encounter. Also, be sure to vary tactics and use terrain features (Paizo is usually pretty good about providing initial battle plans in the encounters).