D&D 5E Young dragons are appropriate for what PC level?

[Yunru]

Take away a young dragon's multiattack, and they're roughly equivalent to a level 7 character, in terms of damage output. Haven't checked defensively (was only investigating the possibility of using them as mounts).

 

[Azzy]

I made a similar mistake once with flameskulls. They're only CR 4, but when you start having multiple ... talk about good gracious great balls of fire!

I've done the same. oh my!

 

[Quickleaf]

I'm working on a campaign about a dungeon that is contested by five dragons--young dragons. They are striving against each other--and the PCs--for control of the dungeon. As stated in the Monster Manual, these are the challenging ratings of each chromatic dragon:

CR 6 - Young White Dragon
CR 7 - Young Black Dragon
CR 8 - Young Green Dragon
CR 9 - Young Blue Dragon
CR 10 - Young Red Dragon

At what level do you thing PCs could fight and survive each dragon?

If the dragons had lair actions, how much would that increase the difficulty?

Thanks in advance for sharing your insights and real world experience!

How many PCs, of what levels, and what class/subclasses/roles?

And do you use feats & magic items?

Do the dragons have ample room to fly around?

Are there any minions or you asking about just the dragons solo?

Will the PCs be fresh or already wounded/resource depleted?

Need more information to even begin to answer. When it comes to lair actions, my rule-of-thumb is that lair actions may increase the monster's CR by +1, provided there are "significant" boosts to offense or defense. However, to know for certain, you need to calculate the monster's CR from scratch (and remember CR is just a loose guideline), and you may sometimes find that the Monster Manual's math is off compared to the DMG since the MM was produced before the DMG guidelines were finalized.

For example, a red dragon's lair actions include magma eruption (21 damage, DC 15 save). What influence does that have on its CR?

Well... here's the DMG calculations on the Young Red Dragon...

Defensive CR
hp 178, effective AC 20 (18 + 2 saves) => defensive CR 10

Offensive CR
Round 1: Breath Weapon, save DC 17 (56 * 3 targets = 168)
Round 2: Bite, Claw, Claw, attack +10 (20 + 13 +13 = 46)
Round 3: Bite, Claw, Claw, attack +10 (20 + 13 +13 = 46)

(168 + 46 + 46) / 3 = 86.7 => offensive CR 13

Total CR
(10 + 13) / 2 = CR 11.5

So, to begin with, the young red dragon's CR in the MM is lower than what the DMG would give you. Which just goes to show how rough the whole CR system is and isn't intended to be a precise tool.

Now, normally when we say "would such-and-such make a good challenge" or "at what level could PCs could fight and survive this monster", what we're saying is "I want to make this fight HARD, a rewarding challenging, but not unbeatable." So, that's when you calculate your party's HARD threshold using the DMG.

So assuming the Young Red Dragon's actual CR (no lair actions) is about 11, and you have a party of four PCs... At 8th or 9th level they would be having what the DMG describes as a HARD encounter.

But that's only the broad strokes. Really, it comes down to knowing your players and their PCs, as well as how you play monsters as a DM.

 

[akr71]

Dragons are not stupid and won't just sit on the ground and take a beating from a party of adventurers. Once it is in the air, it is a lot harder to hit and a lot deadlier. Even a young one is old enough to have gained some wisdom.

If it has a chance of getting caught in its lair where it can't fly, give it some lair actions. Again, they should be played smart - I don't see a dragon giving up its mobility no matter how nice a potential lair might be.

 

[devincutler]

Keep in mind that green dragons are much easier to handle than any of the other chromatic types. Why? Because their breath weapon is uniquely poison and uniquely a gas. This means protection from poison (a 2nd level spell that does NOT require concentration) functions the same way as protection from energy (a 3rd level spell that DOES require concentration) works against every other breath weapon. That is a huge difference...massive actually. A party of 3rd level PCs can basically get fully resistant to a green dragon's breath weapon if there are two of the proper classes in the party. Also, gust of wind works on the green dragon's breath weapon (ready an action...and blow the breath away).

This is why a certain official adventure puts a green dragon up against a low level party.