Hi there, fellow DMs!
I'm a fairly new DM (as in: I have around 20 sessions behind my back), and while my players seem to be enjoying the campaign, I've run into a bit of a problem.
Namely, that the three godsdamned paladins are trivializing most combat encounters.
They just leveled up to level 8, but even at level 7:
- Attack rolls against them? LOL, CR 7-9 enemies usually have +6-+8 to hit at most; they will miss the paladins (and the cleric) in plate armor + shield 60-75% of the time.
- Saving throw abilities and spells? Fuck me, aura of protection, everybody gets +2 or more to all their saves.
- Even if a spell slips through? Ancients paladin. Whoever came up with the Aura of Warding at WotC deserves a kick in the head. Everybody near the paladin takes half damage from every spell (quarter if they make the save) because balancing encounters is soooooooooooooo easy!
And that is just their passive abilities. There's of course the usual issue of smites (the three of them can easily deal 24d8 damage in one turn, that's 108 on average - and that's without accounting for crits or them stacking a smite spell on it too). Ranged enemies? LOL, orbital laser goes BZOT! (Moonbeam) Or they'll just leave them to the ranger, cleric, and the warlock. And if they still get banged up, they have 105 HP of dedicated healing between them (plus the cleric and the ranger).
Is there any way to make combat encounters challenging for this party besides trying to overwhelm them through action economy (it's a party of 6, so that would take a shitton of monsters and turn the combat into a slog), finding a way to force them into 6-8 encounters between long rests (wouldn't do anything about the passive abilities but it would at least curtail the smite-nukes), or turning the game into Dark Souls with every monster being a horrible damage sponge that can one-shot any player on a hit?
Because at this point I'm afraid that anything shy of a tarrasque would be a minor inconvenience at best instead of a challenge or a boss.
I would use attrition. They have 7 spell slots. If they spend 2 of those per encounter, force them to have 4 encounters before they can long rest.
First warn them. Give then a hint that the dungeon is large and will mean quite some time without resting.
Then bait them. For example: an undead unit that has resistences against physical attacks, and does little damage, or is very easy to run away from. Maybe an undead slime blob or gas thing? E.g. https://www.dandwiki.com/wiki/Gas_Wisp_(5e_Creature) They may use their spell slots on divine smites to deal radiant damage. Even though there are plenty of other options in the arsenals of the other 3 players.
Or create a dungeon that forces them to split the party to progress, allowing them to reunite during or after the battle. This could give you several turns where you can exploit the weaknesses of a divided group.
They actually have 9 each with Harness Divine Power. (I don't think they even know what their other channel divinity options are.) Which comes to a total of 27 smite slots per long rest among the three of them, 15 of them level 2. That's 69d8 (nice!) radiant damage just from smites against non-undead, non-fiendish creatures, and without crits or the weapon damage, averaging to around 310.
(And again, I have to ask myself: what the fuck were the WotC peeps smoking when they designed the paladin? HDP for clerics is a minor boost that restores spell slots of their low-level spells, roughly equivalent to the wizard's arcane recovery or the sorcerer's sorcery point conversion. HDP for paladins restores one of their highest level damaging abilities, and they even get the 3/day version earlier than the clerics. As if the already pretty busted base class needed another boost.)
Splitting the party sounds good from the DM's tactical perspective, but it's horrible from the players' fun perspective. It's basically twice the prep for the DM, only for half the party to spend half the session scrolling on TikTok.