D&D 5E (2014) Which monsters would a lone 20th level character struggle to defeat?

[FireLance]

Well, one rather obvious guideline is that action denial abilities (paralysis, stunning, sleep) are going to hit a solo character harder than a party.

 

[auburn2]

Haven't played that high, so have a hard time getting a handle on it. Which monsters would be the hardest to defeat and/or have better than even odds against a decked out 20th level character (any class)? Just curious.

I know the official ruling on CR, but just curious about where the rubber meets the road with actual monsters.

It would depend on the character. If it is a melee fighter, easy something flying that can make ranged attacks .... If it is a wizard something that can hit with damage and cast counterspell .... if it is a rogue something with blindsight or an ability that imposes disadvantage.

Also anything that can target non-proficient saves. For example a mind flayer is only CR 7, and a level 20 fighter can probably take him down in 1 round, but if the illithd is 1V1 with a fighter and wins initiative and the fighter fails a tough int save .... it might be game over right there.

Frankly, a lot of the monsters in the MM would be tough for any player 1V1, even at level 20.

 

[Oofta]

Like others, it depends so much on the scenario.

So as a thought experiment: a Pixie could take out a level 20 PC. They have improved invisibility and a stealth of +7 so should be able to get close enough to cast polymorph on the PC without being noticed. Unlikely to work on anyone with proficiency in Wisdom since it's only a DC 12 but for anyone that doesn't it's still a good chance to succeed.

Okay so you can polymorph. Great. Change them into a tiny creature and probably put them to sleep before stuffing them into a sack. Sleep doesn't break polymorph because you they still have HP, they're just unconscious.

Now it kind of depends on how you run things.

• Can you change things into a bug and tuck them under some boulders? What happens when they revert? Are they just shunted out to the nearest space big enough for them?
• Do you have some prep time so you can just make a container/hole big enough for their normal form and then close the lid so that they suffocate?
• Is there a large body of water around? Polymorph the PC into a salamander so they can breath air or water. Fly out over the water for nearly an hour. Add some rocks to the sack and drop the salamander. The PC will wake up in a few minutes deep underwater and either drown underwater or while trying to swim back to shore. If deep water available, cast entangle as they wake up (you may want to poke them to wake them up). If that's not enough follow it up with phantasmal force to convince them they can't raise their head above water possibly followed up by confusion.

So a CR 1/4 monster could take out a level 20 PC.

 

[GMMichael]

This one.

The Rabbit of Caerbannog

 

[Snarf Zagyg]

"Which monsters would a lone 20th level character struggle to defeat?"

The greatest monster of all!

The monster within.


I have seen the enemy, and he is me.

 

[Weiley31]

This one.

The Rabbit of Caerbannog

This is the reason why my one Druid player wants a Vorpal Bunny as a weapon.

 

[BookBarbarian]

Also anything that can target non-proficient saves.

A chance for a 6 Paladin/14 Monk to show his quality

 

[jgsugden]

It depends upon builds.

A CR 15 monster is a deadly encounter for a solo 20th level PC, but some of them would be easy victories for the right build of PC, while others would defeat any solo PC if competently run by a DM. An ambushing PC may be able to solo much more powerful creatures. I've seen 20th level druids with their unlimited wildshape laugh off a lot of pure damage monsters. On the other hand, some monsters can kill a 20th level PC in a single round.

 

[NotAYakk]

Intellect devourer. Most level 20 PCs have a +0-2 int save.

If the devourer wins initiative, 25% chance the PC fails the save then has its brain eaten before the PC can act.

A 10% chance to die when fighting a low single digit CR monster. Like 35% if the devourer surprises the PC.

Fighters, Monks, Wizards, Paladins, Druids, and Arificers are going to be nigh-immune from saving throw bonuses. Some builds, like Rangers, Barbarians and thise that take certain feats/items, are going to be surprise immune/win initiative. Casters who keep up foresight, or have a simulacrum backup capable of casting wish (or, in fact, any non-trivial minion stronger than a familiar: just kill it before it eats the PCs brain), are also going to win.

 

[Seramus]

How smart is the monster?
How smart is the player?