Level 20 Oneshot/Short Adventure

[ciarannihill]

So a game I run is coming up on the end of the first major arc of our campaign, and we've decided to take a few weeks off from that game for one-shots, smaller adventures and things like that. Amongst the things we're running I'm planning on running for them a level 20 oneshot (or twoshot, depending) -- have them experience epic level play and make it a real challenge for them.

So the question is this: Does anyone here have experience running these types of adventures? What pitfalls have you run into? What might be a fun and epic challenge for them to encounter at the end?

It's a 3 PC game, and I'm unsure of how they would build their characters (though one person said he'd like to try Barbarian 20).

[Rillian]

Things to consider:

1. Players are going to be clumsy with their class. With one shots, players usually pick something they have never played before. Regardless of how much they've read, any player who doesn't have hours of actual playing experience of that class at that level isn't going to know what they are doing and it is going to show. Expect the encounter to grind to a halt frequently so you and that player both reference the books and come to an agreement on how a 9th level spell works or some other high level class feature.

2. The DM is going to make mistakes and bad calls. It's okay, it's going to happen. How are you going to handle that Wish spell? How many pixies are you going to allow from Conjure Woodland Allies so that your Big Bad is barraged with polymorph and confusion spells. Then follow up with Imprisonment once you're out of legendary resistance.

3. Expect your one shot encounter to get nuked. PCs start out full rested, full hp, full spell slots, and they are going to scout and buff up before the fight. Your encounter may last about 3 to 6 rounds, that's it. They will use their strongest abilities first since they don't need to save anything for the rest of the day. On the opening round, expect the fighter to action surge 8 attacks with a great weapon or sharpshooter all with advantage from Foresight (cast by the bard, druid, wizard, or warlock) that's about 200+ damage right there, and again on the second round. If the wizard still has a 9th level slot, expect Time Stop as an opener, or Power Word Kill as a finisher. The rogue will steadily put good single target damage every round with sneak attack, but you'll never find him without True Sight. The cleric will keep the party healthy with most spell slots ready for Heal or Mass Heal, the fight ends too quick for them to shine with Spirit Guardians cast using an 8th level slot.

4. Feats, Multiclassing, and Magic Items are optional in the game's design. These 3 things make your PCs very powerful by the time they reach 20th level. Monsters typically fail contested skill checks. A barbarian with Prodigy: Athletics and Grapple is likely going to get Restrain on your bad guy. Nothing is going to make spell save against that wizard with Robe of the Arch Magi and Staff of Power. You're not going to hit that Life Domain Cleric 1/Necromancer 19 with the 35 AC (plate +3, shield +3, staff of the magi (+2), Spell Mastery: shield spell (+5) = 35 ac) and live through that small army of skeletons.

I'm in a similar spot to you where I'm just trying to run one shots of high CR monsters vs a 20th level party. The monsters I've done so far have gotten chewed up really fast. For encounter balance just use point buy or standard array, standard hit points don't roll them, standard starting magic items at 20th level in the DMG.


Start with an Ancient Red Dragon encounter in it's lair. This site is helpful with monster tactics.
themonstersknow.com

Keep running one shots, you and your players will only get better at them.

[Tubben]

What he said with (3) is very true. I play in an lv 20+ group for a good while now (we reached 20 like a year ago, playing weekly).

You need to bring multiple enemies, if you only bring one ancient dragon, he will be dead faster than you can say hello.

Our DM knows how to make us sweat, and he often bring waves of enemies (depends on where and what we fight). Just dont forget, that the BBEG is not alone :)

[CTurbo]

My advice is that just because they're level 20, doesn't mean that they need silly OP magic items/weapons. I'd go easy on that and maybe let them start with a simple +1 weapon each and maybe one other "rare" magic item.

[Unoriginal]

I'd suggest making a straightforward adventure.

Moloch could be a great final boss.