Good encounters for a high level one-shot

[MightyDuck]

I'm relatively new to DMing 5th edition and I haven't got any experience running higher level games, however, I've promised my friends that I'm going to be running a level 14 one-shot to celebrate the end of our most recent campaign. The party consists of 6 PCs; an ancestral guardian barbarian, revised beast master ranger, GOO warlock, Glamour bard, Storm sorcerer and necromancy wizard. All the players are relatively new and inexperienced, especially when it comes to higher levels of play, so I don't want to make things too hard for them but I'm having a hard time coming up with any encounters. I'm homebrewing the final boss of the adventure but I still need a mini-boss for the very start of the game, something intimidating and challenging but nothing too overwhelming, I then need some encounters, both combat and non, in-between that and the final boss. For context, the one-shot is taking place on an island full of escaped prisoners turned cultist, that have summoned various creatures to the island, so pretty much anything goes in terms of creatures. Any ideas or recommendations? Or should I just throw caution to the wind, take the leap and just try and go it alone?

[Man_Over_Game]

I'm relatively new to DMing 5th edition and I haven't got any experience running higher level games, however, I've promised my friends that I'm going to be running a level 14 one-shot to celebrate the end of our most recent campaign. The party consists of 6 PCs; an ancestral guardian barbarian, revised beast master ranger, GOO warlock, Glamour bard, Storm sorcerer and necromancy wizard. All the players are relatively new and inexperienced, especially when it comes to higher levels of play, so I don't want to make things too hard for them but I'm having a hard time coming up with any encounters. I'm homebrewing the final boss of the adventure but I still need a mini-boss for the very start of the game, something intimidating and challenging but nothing too overwhelming, I then need some encounters, both combat and non, in-between that and the final boss. For context, the one-shot is taking place on an island full of escaped prisoners turned cultist, that have summoned various creatures to the island, so pretty much anything goes in terms of creatures. Any ideas or recommendations? Or should I just throw caution to the wind, take the leap and just try and go it alone?

Look up the Tomb of Horrors. It has plenty of excruciatingly hard encounters designed for level 10-14 characters. Since level 14 is the max level for the module, and Tomb of Horrors is considered insanely difficult at its "appropriate" level, it should balance out to a relatively fun, hard challenge for your players.

[Rukelnikov]

You have crafted a situation where anything goes and there's no campaign repercussions to what they fight.

I would take the opportunity to pit them against stuff they haven't fought before and specially some enemies you like but find hard to place in a campaign. Like fighting some "good" guys, Devas make for nice enemies.

BTW check the Morkoth in Volo's., it fits the theme perfectly.

[MaxWilson]

I'm relatively new to DMing 5th edition and I haven't got any experience running higher level games, however, I've promised my friends that I'm going to be running a level 14 one-shot to celebrate the end of our most recent campaign. The party consists of 6 PCs; an ancestral guardian barbarian, revised beast master ranger, GOO warlock, Glamour bard, Storm sorcerer and necromancy wizard. All the players are relatively new and inexperienced, especially when it comes to higher levels of play, so I don't want to make things too hard for them but I'm having a hard time coming up with any encounters. I'm homebrewing the final boss of the adventure but I still need a mini-boss for the very start of the game, something intimidating and challenging but nothing too overwhelming, I then need some encounters, both combat and non, in-between that and the final boss. For context, the one-shot is taking place on an island full of escaped prisoners turned cultist, that have summoned various creatures to the island, so pretty much anything goes in terms of creatures. Any ideas or recommendations? Or should I just throw caution to the wind, take the leap and just try and go it alone?

Throw caution to the wind and give them some big old encounters. Off the top of my head, something like:

Scenario: cultists are performing a ritual to create a demonic plague that could kill millions. Rituals are ongoing on six points of a hexagon a mile across, so each point of the hexagon is at least half a mile from the nearest other point. (Therefore, the baddies are isolated from each other and you can do each "encounter" completely separately.)

Each ritual point has a hundred cultists doing freaky dark stuff, like sacrifices and obscene dances and gibbering and stuff, plus a few dark defenders. The cultists are noncombatants, and once the dark defenders are dead you can scatter the cultists and destroy that ritual.

PCs enter the scenario at a point where the ritual has just over four hours until completion. (They've been sent back in time to stop the apocalypse, and they were hoping to get there a week before the ritual but, oops, "four hours before it goes off" is where they land.) At that point, the DM will roll a D6, and if that number matches one of the ritual points that have NOT been destroyed, millions die. If PCs move at full speed from point to point around the hexagon, it will take them about an hour to traverse the whole thing, giving them just barely enough time for take three short rests along the way--less than that if they skip some points and come back to them later.

The following encounters are generated off the top of my head, based on what I think would be fun for a 14th level party of six. I'm aware that they are more than Deadly but IME these would be about right:

Point #1: A Nightwalker and four Bodaks.

Point #2: A Purple Worm and two Fire Elementals. Purple Worm will emerge from underground to attack whatever PC is first to set foot within 100 yards of the ritual center. (Will not exploit burrowing.)

Point #3: Star Spawn Seer in a cottage, Star Spawn Hulk out in the open, two Star Spawn Manglers hidden inside a well near the cottage, and twelve Star Spawn Grues around the cottage. (Will exploit synergies between Seer psychic attack and Hulk, as well as synergies between Manglers and every source of advantage (Grue bites and Hulk stuns).)

Point #4: Four brave Efreeti brothers who will fight to the death to protect or avenge each other. (Will exploit flying + ranged attacks to hit vulnerable PCs.)

Point #5: A Devourer, two Banshees, and a dozen Shadows, inside of a shadowy keep (100' x 100' of dimly-lit empty space (light obscurement)). Banshees will exploit their incorporeality to e.g. end their turns inside the ground to avoid attack, taking 1d10 force damage instead of a full attack sequence.

Point #6: A Mind Flayer Arcanist, a Githyanki Gish, and a Githzerai Anarch (all working together!?!) plus three Intellect Devourers hidden inside three of the cultists.

Clearing out all six points would be very tough but maybe doable, especially if they do stuff like e.g. enslave the Nightwalker using the Necromancer's Command Undead feature, using of Wall of Force/Forcecage to divide and conquer tough enemies, using illusions like Phantasmal Force to distract the Purple Worm, etc.

Anyway, that's just an example to get your creative juices flowing. Trust your gut and have fun!