One Big Boss

[Conchobar]

Hey all, going to DM my first campaign here soon, and I just had a question about balance I figured would be easier for some of you long-time DMS out there: Could one fairly optimized level 20 character be a suitably challenging opponent for a party of 5 non-optimized level 12 PCs? I know it's hard to make a judgment call without knowing more information, but I'm just looking for possibilities here. The information I have right now (which is subject to change) would be a Crusader 6/Paladin 4/Ruby Knight Vindicator 10 Big Bad vs. a party of some sort of rogue, some sort of blast wizard, a Warblade/Deepstone Sentinel, a Knight, and a Swift Hunter Scout.

Thanks!

[VoxRationis]

The answer depends entirely on the boss's class.
If they're a fighter-type, I can personally attest to the fact that a difference of 8 levels is not enough to keep the boss alive for more than a few rounds.
If they're a wizard, that's enough and more. The higher-level spells can give the boss all kinds of ways to prevent the party from doing anything.
I'm not sure what, if they're a rogue or something.

[Red Fel]

Could one fairly optimized level 20 character be a suitably challenging opponent for a party of 5 non-optimized level 12 PCs?

Short version? Define "challenge."

Assuming your BBEG operates under standard game mechanics (i.e. one swift, move, and standard action per turn, as-written spells and abilities, etc.) it will be a curb-stomp. Either the party will run over him like a steamroller, or he will shred each and every one of them to pieces - there's really no satisfying in-between point with a single-enemy encounter. And chances are good that it will be the former.

The reason, as often stated, is the action economy - for every one action the BBEG can take, each player can take an action. That's five actions to his one. And if only one of them manages to lock him down, it turns from a boss fight into an absolute slaughter.

There are ways to make a BBEG a challenge, of course. Make him tougher, so PC hits have less impact. This helps him last. Make him stronger, so he drops PCs more quickly. This creates a sense of urgency, which is valuable when the PCs have the action economy on their side. Or give him extra actions in each round, which removes the action economy.

Another alternative, and one that runs contra to the nature of a solo boss encounter, is minions. A level 20 character with a single Summon Minions spell can spit out a large number of expendable mooks. This can substantially shift the balance of the action economy, and obviate the need to alter the BBEG's mechanics.

But short answer? The action economy has a tendency to make these battles anticlimactic. Either the PCs are strong enough to face the BBEG, which means they'll take him out in short order, or the BBEG is too powerful, in which case he will steamroll them. No in-between.

[Conchobar]

"Challenge" here meaning that with teamwork and some close calls, they could take him down eventually. Ideally it'd be at least something of a tense fight, rather than a game of rocket tag.

I went with the RKV because of its ability to abuse the action economy, hoping that it would narrow the gap caused by facing five people at once. He's also pretty tanky, and as you can see the party as it is right now isn't exactly focused on battlefield control or anything like that. I was kind of worried that it would end up being a situation where the boss is either too slow to be effective or the party is too weak to be effective, and it sounds like that's generally the case. Guess I'll have to throw in some lower leveled cronies to soak up some of the fire in the early rounds.

[iceman10058]

they may have a hard time, but i think as long as you don't seek out to kill the party but to challenge them it should be alright.