Is Lost Mines of Phandelver’s Young Green Dragon too much for a group of level 3 characters?

My group of 8 level 3 players are about to run through the Thundertree Ruins and will probably have a hand at fighting the dragon. My question stems from the fact that a single poison breath attack from the dragon will outright kill all but 1 player assuming they fail their saving throws.

I understand this encounter is supposed to be ridiculously deadly, but I don’t want to be punishing my players for testing the lengths at which they can fight stuff. A fight should be challenging and they should be able to try and run away, but instant obliteration seems a bit much.

All PCs are level 3 (HP in parenthesis):

  • Wood elf moon druid (27)
  • dwarven frenzy barbarian (44)
  • fire genasi archer ranger (37) (pseudodragon companion (12))
  • wood elf assassin rogue (27)
  • human wild magic sorcerer (22)
  • dragonborn fighter (29)
  • human monk (24)
  • human fighter (32)

Can an Eldritch Knight Attack Twice With Green Flame Blade and War Magic? [duplicate]

An 8th-level Eldritch Knight has a sword.

The War Magic class ability says:

When you use your action to cast a cantrip, you can make one weapon attack as a bonus action

And the cantrip Green Flame Blade says:

You brandish the weapon used in the spell’s casting and make a melee attack with it against one creature within 5 feet of you

So I think that means there are 2 sword attacks in total for that turn.

One attack is a bonus action, and one is a side effect of the cantrip. In addition to that are the flame effects of the cantrip as well.

(The 2 attacks are not related to the Extra Attack Fighter class ability, which requires taking the Attack action, which is not being done here.)

Is the above information correct?

What is the highest armour class possible for an Ancient Green dragon?

This posts asks what the highest armour class may be for humanoids. Similar to this question, i would like to know what the highest AC would be for a monster. Narrowing this down, let us look at improvement techniques possible for an ancient Green dragon. As this is a BBED (‘Big Bad Evil Dragon’), they most likely have a slew of minions, guardians and servants – so please feel free to use any options that exist (in 5e) that may be spells, minions, a spare shield guardian, or anything else you like.

For stats on the ancient Green dragon, has a base dexterity of 12 and a base AC of 21. I do not know if it could gain NPC levels of monk or barbarian, nor what use that would have. We can assume this dragon has the ‘optional’ spell casting abilities. According to old (possibly 3.5e) Forgotten Realms material these creatures are a minimum of 800 years old at ‘ancient’ and may live until past 1,200 years or more. They seem to have access to a lot of magic items. These things are gargantuan, so i have no idea, for example, what size shield they would need – or even if a shield works for them. I don’t even know how big ‘cover’ would need to be in order to offer 3/4 protection. Would a Cloak of Protection even fit? I have specifically left this quite open as i would greatly value any and all possibilities that Stack Exchange has to offer.

Let me know if this question is specific enough. The original (above) was seemingly less specific, but Stack Exchange seemed to be enjoying a different mindset at that time.

Question Recap: What is the best armour class possible for a 5e ancient Green dragon – assuming any & all options are available to it.

Can the blade created by Shadow Blade be used with the Booming Blade or Green Flame Blade cantrips?

The spell shadow blade allows a spellcaster to produce a discrete weapon that can then be used to make attacks:

You weave together threads of shadow to create a sword of solidified gloom in your hand. This magic sword lasts until the spell ends. It counts as a simple melee weapon with which you are proficient. It deals 2d8 psychic damage on a hit and has the finesse, light, and thrown properties (range 20/60). In addition, when you use the sword to attack a target that is in dim light or darkness, you make the attack roll with advantage.

Shadow Blade, Xanathar’s Guide to Everything, pg. 164

As part of recent errata to the green-flame blade and booming blade cantrips, their material components have been amended to "a melee weapon worth at least 1 sp" (Sword Coast Adventurer’s Guide, 142).

Can shadow blade still produce a weapon that can be used with these cantrips?

War caster feat and green flame blade, is it legit?

The War Caster feat allows a single-target spell (“must target only that creature”) to be cast instead of a melee strike for an opportunity attack.

Green-Flame Blade appears to have a single target, and then some damage “leaps” onto a creature 5 feet away. The other creature is never referred to as the target, or even “a target”.

I’m pretty sure this is solid from the RAW perspective. Is this legit from a RAI perspective?

if booming blade or green flame blade are counter-spelled, does the attack still go through?

Booming blade says:

As part of the action used to cast this spell, you must make a melee attack with a weapon against one creature within the spell’s range.

Counterspell reads

You attempt to interrupt a creature in the process of casting a spell. If the creature is casting a spell of 3rd level or lower, its spell fails and has no effect.

Does counterspell interrupt the attack made in conjunction with casting booming blade?

Gust of Wind vs Green Dragon Breath

I think this is similar to Can Warding Wind block the effect of a Green Dragon's Poison Breath? but the wording of Warding Wind seems more conservative than Gust of Wind.

I just ran a combat where a druid used Gust of Wind against a green dragon. I had the dragon retaliate by flying (slowly) towards the druid and using its breath weapon. The players were delighted, immediately declaring that the monster’s attack should have been nullified because:

[Green Dragon] The dragon breathes poisonous gas in a 30-foot cone

[Gust of Wind] The gust disperses gas or vapor…

However, I ruled that the breath weapon worked as normal through the line of the wind, using similar logic to the most upvoted answer on the linked question, that "dispersing gas" is for handling cloudkill, wall of fog and other lingering effects that explicitly describe being dispersed, and that breath weapons (or other instantaneous area effects) do not get cancelled through dispersal. Instead, I would argue, breath weapons may only get blocked by spells that say it more directly e.g. Wind Wall which says that it "keeps gases at bay".

It would not have been a big deal if the players were correct in my case, as the dragon had other tactical options – moving out of the of the gust of wind to attack from the side for instance – so the ruling did not change much about the outcome (although it disappointed the players because they were convinced they had outsmarted the dragon and made it lose an attack). And in the end the battle was won by the PCs.

Should I have allowed Gust of Wind to nullify gas-based breath weapon attacks made within it, according to rules as written? What exactly does "dispersing" mean in the Gust of Wind spell description?

Dnd 5e Green flame blade and Flames of Phlegethos stacking [duplicate]

I’m playing an eldritch knight, and I’m looking to optimize the damage of green flame blade. The feature “flames of Phlegethos” states that “When you roll fire damage for a spell you cast, you can reroll any roll of 1 on the fire damage dice, but you must use the new roll, even if it is another 1. Whenever you cast a spell that deals fire damage, you can cause flames to wreathe you until the end of your next turn. The flames don’t harm you or your possessions, and they shed bright light out to 30 feet and dim light for an additional 30 feet. While the flames are present, any creature within 5 feet of you that hits you with a melee attack takes 1d4 fire damage” would both the 1d4 fire damage and the re-roll 1’s on fire damage trigger when using green flame blade? Or is this meant for spells of level 1 and higher?

Dnd 5e question. Combination of green flame blade and the tiefling feature “flames of the nine hells”

I’m playing an eldritch knight, and I’m looking to optimize the damage of green flame blade. The feature “flames of the nine hells” states that “You deal 1d4 fire damage when hit by a melee attack and shed 30 feet of bright light after casting a fire spell, you can reroll 1s on spell fire damage rolls” would both the 1d4 fire damage and the re-roll 1’s on fire damage trigger when using green flame blade? Or is this meant for spells of level 1 and higher?