D&D 5E Need help on how to handle a huge fight

[dave2008]

Sure, but I don't know its red. Other ancient dragons have much fewer, so I was going on the lower end to play it safe. The ancient red has AC 24, meaning a nat 20 would be needed to hit (throw in disadvantage, and only 1 in 400 arrows would even hit). So, I assumed a more modest AC 21.

Ha! I just assumed red dragon when I read that - I guess my bias is showing! However, an ancient red has an AC of 22, not 24.

Regardless, you're correct in taking a more conservative approach.

 

[DND_Reborn]

Ha! I just assumed red dragon when I read that - I guess my bias is showing! However, an ancient red has an AC of 22, not 24.

Regardless, you're correct in taking a more conservative approach.

LOL, really? I always thought it had the same as Gold? Huh... NM, I just checked, they are BOTH 22... weird. I don't know why 24 was stuck in my head... maybe from the CR.

But yes, a more conservative ancient dragon would kill thousands, literally, before any "army-type" force could stop it.

 

[Hatox]

Yes I calculated it with an ancient green dragon (ac 21 and a bit below 400hp). Like you said, if the archers see the dragon coming, they can fire before being in his frightful presence, meaning about 1/5 of them will hit, lets say theyre goon-level and have +2 dex +2 proficiency. They´ll hit for an average of 6 damage per 5 archers, meaning 200 of them should deal about 240 damage (not calculating that about 1/4 of those hits should be crits). So in the first round the dragon should loose a bit more than half HP, but youre right afterwards it gets interesting, if the dragon doesnt retreat, he can use frightful presence, breath attacks, maybe even spells, but its not like he´ll get out of it without being severely injured.

 

[dave2008]

Yes I calculated it with an ancient green dragon (ac 21 and a bit below 400hp). Like you said, if the archers see the dragon coming, they can fire before being in his frightful presence, meaning about 1/5 of them will hit, lets say theyre goon-level and have +2 dex +2 proficiency. They´ll hit for an average of 6 damage per 5 archers, meaning 200 of them should deal about 240 damage (not calculating that about 1/4 of those hits should be crits). So in the first round the dragon should loose a bit more than half HP, but youre right afterwards it gets interesting, if the dragon doesnt retreat, he can use frightful presence, breath attacks, maybe even spells, but its not like he´ll get out of it without being severely injured.

Interesting how much easier a fight it is for an ancient red

 

[DND_Reborn]

Yes I calculated it with an ancient green dragon (ac 21 and a bit below 400hp). Like you said, if the archers see the dragon coming, they can fire before being in his frightful presence, meaning about 1/5 of them will hit, lets say theyre goon-level and have +2 dex +2 proficiency. They´ll hit for an average of 6 damage per 5 archers, meaning 200 of them should deal about 240 damage (not calculating that about 1/4 of those hits should be crits). So in the first round the dragon should loose a bit more than half HP, but youre right afterwards it gets interesting, if the dragon doesnt retreat, he can use frightful presence, breath attacks, maybe even spells, but its not like he´ll get out of it without being severely injured.

Well, if the attack is happening during the day your dragons are not very intelligent.

On a dark night, your dragon can see 120 due to its superior darkvision, as where your goons won't even be able to see it to shoot (except the dwarves with 60 darkvision). But that means they can move into fear range and breath before the goons can even see it. The dragon could fly over head, land behind the enemy lines, and breath then start flying away again.

Even during the day, you are forgetting those attacks beyond 150 feet have disadvantage, nearly all within 120 will also have it due to fear. So, the odds for most of them to hit is really only 3.5%, slightly better for the few who make the DC 19 WIS save. Also, not all 200 will be grouped so closely to shot together (if they are, one breath will wipe most of them out!), many will probably not even be within long range as they are likely spread out along the city walls. More reasonably, I think you might get 5-10 that are close enough and will actually hit, doing 30-60 damage in that first volley, not the 240 you think.

Sorry, it is one of my pet peeves when it comes to dragons. I've seen WAY to many groups not play dragons as they should be IMO given their insane mental abilities (your ancient green dragons have INT 20 and WIS 17!) and age, hunting experience, etc. If I was the DM, the party would be sorely pressed to save the city against a single ancient dragon, let alone TWO!

That is why I initially responded focus on the PCs against the dragons, with the rest being background noise, and hope it isn't a TPK.

EDIT: as @Oofta mentioned (I think), siege equipment is the city's best hope against dragons. Better range, better chance to hit, better damage.

 

[DND_Reborn]

Interesting how much easier a fight it is for an ancient red

Against TWO ancient red dragons, the PCs should flee and as a DM, I would narrate the horrible destruction of said city.

 

[DND_Reborn]

@Hatox:

I would only have one dragon lead the initial attack if the PCs are only expecting one. Then have the other attack from another direction, possibly adding their horde army into overwhelming the city defenses.

Sorry, but with the PCs you have, I see this very much as a TPK if you do both dragons at once. None of the PCs sound like tanks (I could be wrong of course), and the damage output of the dragons will likely kill one PC per round. Now, I have no idea what knowledge they have beforehand nor what magic items they might have, so maybe I am underestimating the party. I hope that is the case.

 

[Oofta]

I think running dragons (and other monsters) intelligently could be a whole other thread.

I have never had a party successfully take out an ancient red dragon, let alone two. Caused them to run away? Yes, once. But the dragons aren't going to just land and say "come get me". As others have stated they're incredibly intelligent; you don't live to be a thousand years old by taking risks.

The only reason Smaug was killed in The Hobbit was because the plot demanded it and they had a ballista bolt of dragon slaying.

But ... it's not my campaign.

 

[Hatox]

The combat should be a challenge, but far from an easy tpk, even if they fight both at the same time, they will probably start fighting one, with the other one joining after a few rounds. They are pretty well equiped and tankier than you would expect. Their ACs range from 18 to 23(some because of multiclassing e.g. rogue/cleric and bard/paladin some because of magic items), they know exactly what dragons they are fighting (Black and Green, meaning they will probably all drink antitoxins before the fight gaining advantage and resistance against the green one). Also the green one (spoiler hope none of my players fall over this post) is only a simulacrum (bent the rules a bit on that one since technically sim can only be cast on humans/beasts but it was just to fitting for the "deceiving" dragon) which means it only has ~180 hit points.

 

[Shadowdweller]

In a military situation, I tend to figure that if the dragons aren't making night raids and don't have cover from the environment, they're probably using petty minions to MAKE cover (cast spells that conceal the dragon, or push around giant mantlets / siege-enging like devices or something) so that the dragon can quickly fly out and breathe on the enemy, then return to safety from potential archers.