Valador
First Post
To counter PC with high AC, I use Rust Monsters at appropriate situations. I will use curses/banes to wither down a PC's fighting prowess as well. Introduce curse on holy-looking item. Paralyze him with magic for a few turns if needed.
Enemies that work effectively in a group can also be used against a lone PC. For my current campaign, I am introducing a Vengeance Paladin NPC to be rescued. The captors are Hobgoblins with their Warlord. Hobgoblins have martial advantage and leadership, particularly good for taking down single entity like a lone Paladin with a few hobs surrounding it.
The trick is not too be too obvious such that the paladin PC feels you are biased and deliberately throwing stuff to bring him down to his knees.
So basically it's DM vs. the player and the trick is to not appear you're being biased, when in fact you are? Really? So let's penalize someone due to the class they picked to make everyone else feel better? The paladin isn't even the top melee class in this edition.
I'm all for presenting the other players hand tailored challenges and situations to let their classes shine, but I'm not for witch hunting someone based on their class. More out of combat situations, more monsters of lower levels to offset the Paladins single target damage spikes while allowing "weaker" characters to contribute, and more frequent encounters to drain resources.
Not some kinda "10 kobolds all run past you to attack the paladin using pack tactics with their +3 paladin slaying swords and by the way, all of your armor was cursed and now you have 10 AC" mess...