Need help (suggestions) making final battle more challenging

[Craig1234]

I have been too lenient allowing my players to get their hands on magic items and ultra-high quality gear in this campaign (to be fair, it's my first campaign, so I didn't expect it to be a problem until recently) and the result is that they are almost untouchable. For example, this is a party of 3 level 16 characters who in our last session took on a CR20 fight and the PCs only got hit twice the entire battle, which was short because they never missed and did massive amounts damage every time with every hit.

They're just coming into Xin-Shalast now, so they just have to get through the city before the final battle, and I'm worried that the final battle will end up being anti-climatic, which would be a real shame. As such, I'm hoping to scale up the CR of the final battle (in the book its a CR22) so that it is very challenging but don't know how to do it. My guess is the final CR would need to be around 25-26, and I also don't want to add any other bad guys to the mix, so it would be a case of doing some leveling on the 5 monsters in the fight or adding defenses to the eye of avarice itself. Any suggestions for how to improve this situation?

Thanks

[Craig1234]

think I found my own answer, but still feel free to present any other ideas.

My party had let Lucrecia escape and I think its only fair that she gets another turn at them, so I'm adding her (leveled up to a CR19 on her own) into the final battle, which will make the entire battle a CR 23.

[Askar Avari]

I know there's also a thread back down a ways (2018 maybe?) about modifying Karzoug's equipment and spell list to make him a more challenging opponent - that's probably worth looking into if every action he takes really needs to count.

[Mudfoot]

You could have Karzoug preemptively targeting the problem equipment. Fudge in some way for him to drop a Disjunction now and again when they're still in Xin-Shalast. So that this doesn't sound too arbitrary and unfair, make sure that it involves some manner of conduit (be that a creature or effect) and warning (distinctive lights, smells, noises, etc) so the PCs can learn how to stop it. Naturally this can sometimes coincide with some other major encounters.

After all, K is going to use ever tool he's got to stop them, and they're now on his home turf so it should feel like it.

[Craig1234]

I'll be sure to try those things. I worry about taking out the weapon effects before the final battle as I know these guys are keen enough to simply wait until the next day before entering the portal, thereby recharging the effects.

[Phntm888]

Here's what I did:

First, I reconfigured Karzoug's feats. He doesn't need that many Item creation feats for this fight, and Arcane Strike and Combat Expertise do nothing. I gave him a couple extra Spell Focus feats, as well as some more metamagic feats, Additional Traits (to give him Reactionary and Magical Lineage), and Improved Initiative.

Second, I gave Karzoug 2 Mythic Tiers of Archmage. This gives him Mythic Surge to use when he makes saving throws. For Archmage Arcana, I gave him arcane surge (expend mythic power to cast an arcane spell as a swift action without expending a spell slot). His path abilities were Mythic Spellcasting (contingency and dimensional lock), and for his Mythic Feat I gave him Mythic Improved Initiative. With a total Initiative modifier of +18 and the ability to spend a mythic point to treat his roll as a nat 20, I basically ensured he would go first.

You've already added Lucretia to the mix, which is good. I added bodies as well. An extra rune giant might not hurt things, either.

I also adjusted his spell list. Undead body IV, a transmutation spell, allows him to gain incorporeal as a trait (ghost Karzoug). I used undead body iv coupled with a scroll of project image to trick my players into thinking he was still on his throne while he hid in the floor and walls, casting spells from his projected image.

My players got him with irresistible dance, which made it so he couldn't manage hit and runs anymore, but otherwise it went pretty well.

[Bellona]

My suggestion:

Spoiler:

Wall of Suppression (APG) just where the PCs arrive. Can they survive without their spell buffs and magic items?

Just make sure that Lucrecia (or whoever) is ready to counterspell any Dispel Magics that they might throw at that wall or its effects.