Party first time facing a rather informed opponent

[HoboKnight]

Hey guys,
for the first time, my party is facing an enemy with high meta-knowledge and an option to fully observe the PCs. It is an adult green dragon.

Dragon has just recently moved into a local swamp(in fact resides in an abandoned and defiled temple of Bahamut in steep hills at the very edge of the swamp). 1-mile radius is already affected by his presence, so hedges are growing and small animals work as cameras via which, dragon can observe an entire 1-mile radius.

At the foot of the hills, there is an entrance into a small dungeon, populated by a small kobold tribe - they are servants of the dragon, they adore but also very much fear the great green serpent. The kobold dungeon ascends in the hills and the back exit leads to a large gorge, connected by a hanging bridge. On the other side, there are again steep hills, with another dungeon entrance at the bottom. First dungeon is full of goblin warriors, loyal to the big bad beast, and this dungeon connects to another one - filled with hobgoblins. Among the hobgoblins and goblins there is a significant number of low-tier spellcasters. Rear exit of this dungeon leads to a massive temple on a small grassy plain, huddled among steep mountains. Dragon resides in it.

Now, given his ability to spot a massive region around his lair, the dragon has spotted the party approaching. They are seven riders on five warhorses. One fully armored dwarf, one fully armored elf, one fully armored human, one gold-scaled, fully armored dragonborn and a halfling(small, stunted creature). With them are two bullywugs, locals, probably guides and traitors, given they are guides for the interlopers. Dragonborn really rubs the Big Green the wrong way. He wants to see him captured and tortured for as long as his body withstands the torture.

Swamp would probably kill lvl1-2 adventurers, so party must be higher level. Their heavy armor indicates large funds. They have mounts, which are not really expensive, but there is a massive elk among them too. Fishy. Could be a druid or something similar.

Dragon has little intention of letting the party enter the caves and slaughter his minions. On the other hand, this would be a good assessment of the party's power. But losing minions also means less veneration and adoration and that kinda sux.

Dragon knows that when armored interlopers enter the dungeon, there will be no chance of a breath weapon attack/flyby attacks. Perhaps the best thing to do would be to fly out, talk to them, then douse them in poison and see what happens. But the dragonborn should be caught alive. Perhaps ALL troops should be pulled back into a single dungeon? But again, his troops are difficult to control. More a mob, stabbing, slashing and throwing fireballs, then a real army.

The group is at a steady pace advancing over the swamp. Dragon must make a decision. How to go about it?
thanks.

[Mastikator]

Send an emissary to speak with them, find out their intentions and seek a peaceful resolution (but actually only collect information, since the only peaceful resolution the dragon will accept is surrender). Dragons have the ability to uplift a creature into a dragonborn, perhaps a kobold can be uplifted and at the same time turned into a draconic sorcerer. The dragon should not try to talk to them directly if it suspects a druid.
If it does eventually engage them it should do it in the open, use breath weapon to get them to split the party, then pick whoever is the farthest away and grapple them, then fly them into the air.

Basically: 1) gather intelligence, then 2) divide and conquer

[J-H]

What resources does the Dragon have? Any spellcasting or casters available?
I would go for "talk to them while invisible and out of range of Dispel Magic" and "when the fight starts, open with Entangle."

Definitely engage outside of the lair, as that offers the ability to retreat when lowered to 1/2hp, spend two minutes chugging healing potions, and then return.

Bring any low-level casters along and have them fight from 3/4ths cover a couple of hills away from the path, spamming Faerie Fire, Entangle, and the like.

[da newt]

Traditionally a tribal band of Hobgoblins is a very well disciplined martial unit more than capable of well coordinated and disciplined combat maneuvers / tactics / strategies. Unless these are uniquely passive / dumb Hobgoblins, this Green has a well trained army at it's disposal.

Goblins are excellent scouts and ambushers.

I'd be tempted to let things unfold w/ the Kobold (sacrificial / consumable items) while observing and gathering intel all while plotting for a well planned / prepared and coordinated defense / war with my goblinoid army from well fortified positions. The Green himself ready to swoop in and devastate the interlopers once they are engaged / preoccupied with my main forces.

[Kurt Kurageous]

The strategy is to wear down the party. That means the dragon has to stop them from resting. What I don't know if the dragon has enough time to do this. If there's not enough time, then the dragon has already lost. A mile within the lair might not be enough time. If I were the dragon, I would not bet on it. Especially if they can move faster mounted. A flying mount is definitely a greater threat that must be eliminated.

Now on to tactics.

Disable (poison) or kill the mounts for an opening act. You don't have to kill them all, just enough so the party is slowed down by the unmounted member. This is a job for the minions. Kobolds in spider holes pop up to 5' and dodge whilst hobgoblin archers with martial advantage from range focus fire. Everybody splits when the first mount dies. And by dies, I mean beyond the reach of healing (two arrows negates all death saves even if the mount was allowed them). Truth be, the hobbie archers might as well shoot at max range, because they will already be disadvantaged when the mount falls prone...

The dragon needs to find the time and the place for a decisive action. There has to be a decisive piece of terrain and/or a set of conditions favorable to the dragon and unfavorable to the party.

One such opportunity will occur if most or all of the party can be brought to 3 levels of exhaustion. This makes them disadvantaged to both the frightening presence AND the breath weapon. The dragon will have them in open terrain no matter how many HPs they have unless they have a better standoff weapon.

Another advantage is being able to glide down in the dark to 60' above and breathing gas. This could make nights very long and potentially exhausting. Kobolds lobbing burning pitchy pine or oil-soaked objects to dimly light the party would be enough to guide the dragon in for a strike.

This might lead to the party getting up and running away. But they can't go fast without risking running into dangerous terrain like quicksand or pools of muddy water. Which leads to...

Heavy armor means you can't friggin' swim. Putting water into the fight could split the party up with some members under water awaiting rescue, others able to walk, others swim, and perhaps others breathe underwater. If the party was not prepared for water, it will amp up the difficulty level quickly.

And did I mention this dragon can swim? The dragon can practically disengage whenever it wants with a swim speed of 40'. I dont know if the DM would allow it to do flyby or a wing attack under water. The damage doesn't matter, but knocking a foe prone and the additional movement while trying to get away lets the dragon do a below water strafe like it did in the air.

If I knew more about the particulars, I might be able to come up with more.

As far as 'fly out, breathe, and see what happens,' this is incredibly stupid. A power used is a power diminished. Once the enemy knows what you can do, they can counter or at least mitigate it. That's why the dragon should only engage at the decisive moment. Sorry, but a smart dragon plays to win and doesn't play around and find out. Make sure your players know the stakes. Most PCs expect to win every fight they choose because "balance."

As far as 'grapple, fly up and drop' goes, this is a excellent approach, especially if the dragon is also flying away from the party. Dropping an armored foe in a nearby pond is especially good for reasons previously explained.

[Sorinth]

From the dragon's POV using the goblins as a probing attack would make some sense. They have good stealth for an ambush and can disengage easily, so a small war band of goblins makes an ambush tries and flee after round 2 (Unless it looks like they are winning). Maybe have the kobolds setup some traps along the escape route in case the adventurers try to chase them down.

Since Goblin's have the same Stealth as the dragon, it can give them a good idea on whether they will be able to successfully ambush them as well. And they might get a better idea of whether the party would survive it's BW.

After the probing attack it has more options/info and can decide to lay it's own ambush, have it's minions leave a false trail to make the lair harder to find, suborn the guides into leaving them alone in the swamp after stealing all their food/water, etc...

[JackPhoenix]

One thing to note is that green dragon's breath weapon ignores (non-full, but seeing as it's gas, I could see argument for ignoring full cover in certain circumstances too) cover, because it's Con save, not Dex save or attack. The dragon can simply gas the party through the tree canopy (if there's one) without having to worry much about retaliation.

[HoboKnight]

Seems ti me, there are like 7 people on this forum. :D Always the same helpful souls, thanks so much, guys.

I think the plan is: send out a group of kobolds, followed by a group of "barrier troops" - hobgoblins that threaten to kill the kobolds, if they get out of line. Kobold task is to talk to unwelcome guests/prey/tribute, while dragon observes the interaction via critters/birds in the swamp.

Can dragon assess party by observing them via critters?(what would he roll for threat assessement?)

Adventurers may want an audience... in this case, they must come unarmored and unarmed and will be recieved on a hanging bridge above the gorge.
Shoul things turn violent, bugbear barrier troops fire at the interlopers and flee into the dungeon, wanting to lure the opponents in the dungeon with a goal of "testing" the adventurers and with a goal of grinding them down.

This is the plan ATM.

[Kane0]

Get the hobgoblins to send out a 'meeting party', with some goblins to ambush during 'negotiations'.

Then, tell the kobolds about this separately. Their job is just to trail behind the goblinoids and report on what happens.

If the hobgoblins win, great!
If they lose, the kobolds inform you and you prepare either a second wave/strafing run on the weakened party or secure your dungeon for the incoming attack.

[Unoriginal]

Get the hobgoblins to send out a 'meeting party', with some goblins to ambush during 'negotiations'.

Then, tell the kobolds about this separately. Their job is just to trail behind the goblinoids and report on what happens.

If the hobgoblins win, great!
If they lose, the kobolds inform you and you prepare either a second wave/strafing run on the weakened party or secure your dungeon for the incoming attack.

Hobgoblins are generally too honorable to attack when the other side has agreed to negotiations.

But I think the Green Dragon could convince them to have the goblins hide around as protection, saying "if the adventurers are homorable, they won't attack you once the negotiations are over. If they are ruffians who wish to attack an envoy of peace, however, it is better that you are more protected than they realize."

[Keravath]

A few questions ...
Is the dragon a spell casting variant? Can it change forms?

Without at least Misty Step, any dragon is vulnerable to several spells available as early as 7th or 9th level characters. Wall of Force + Sickening Radiance for example though this party doesn't appear to be capable of that sort of threat.

Do the adventurers look stupid? A green dragon has intelligence 18 - they would assume that if the party is heading out to his lair, they know he is there, they likely know he is an adult green dragon. If they are approaching this means that they consider themselves a threat, so he needs to consider them a threat as well.

What are the dragons goals and objectives? Is the dragon over confident? Have any other dragons been killed recently? Dragons can live a very long time. Although only some have a disposition to be patient, a green dragon often likes to use misdirection and trickery to achieve its goals and they can't achieve those goals when dead.

Keep in mind that the lair will be surrounded by thickets that impair and channel movement as well as a mist or fog that can partially obscure vision - within the same 1 mile radius that the small animals can be used as scouts.

Also minions can include a number of creatures ...
"Green dragons accept the servitude of sentient creatures such as goblinoids, ettercaps, ettins, kobolds, orcs, and yuan-ti."
So .. you might want to toss in some yuan-ti for added challenge :)

In terms of attitude ...
"A green dragon stalks its victims as it plans its assault, sometimes shadowing creatures for days. If a target is weak, the dragon enjoys the terror its appearance evokes before it attacks. It never slays all its foes, preferring to use intimidation to establish control over survivors. "

The text does not say what the dragon would do against strong opponents but my guess would be they would instruct their minions to focus on specific targets and make sure they are dead before moving on to the next. However, they would also instruct the minions to just subdue the last one or two since green dragons love prisoners.

---

Anyway, I think the dragon's battle plan might be something like ..
1) Ambush the party with minions killing the guides (traitors) and the horses then withdraw.
2) Ambush the party again with minions with all of the attacks focusing on one character AND these attacks continue even after they hit 0 hit points to ensure that they stay down (unless the party has revivfy). A green dragon is smart enough to recognize the issues with healing unconscious characters by either spells, abilities or potions, and they will make sure that the first one or two in the party are truly dead before trying to subdue the rest. This may be a threat the party has not encountered before and may come as a shock to the players if the DM has typically had monsters not attack players who are at zero hit points. However, the DM should really emphasize that this is an intelligent and wily opponent who understands the ebb and flow of battle and how to WIN. This greatly increases the danger when every creature attacking the party focuses attacks on downed characters until they die. An attack against an unconscious opponent within 5' is a critical hit and each hit inflicts 2 failed death saving throws. Two hits within 5' against an unconscious opponent will kill them and they won't be getting up.
3) The dragon would then assess the effect of the first two ambushes/battles.

You need to keep track of the forces the dragon has available and decide how much of those forces get allocated to each ambush and what forces remain. If the party proves successful and powerful, the dragon is smart enough to assess the party abilities and decide if it is safe to remain.

The dragon may have established connections to local governments, infiltrated organizations with followers and might be able to set up the party to be attacked by local forces/authorities if the dragon is forced to leave their lair.

If the party appears weakened then the dragon might put in an appearance, hit them with a breath weapon and intimidate them into leaving or serving them.

4) Traps within the lair. There will be deadfall ceiling traps where the dragon tries to drop the ceiling on the characters. They will also have other traps where the ceiling falls in front and behind the party then a valve is opened from an underground river flooding the section and drowning the party. These won't kill a decent party but they will further allow the dragon to assess the capabilities of the party in action since they will be watching with small creatures.

5) The party will not be allowed an uninterrupted short or long rest. Within the mile of the lair, the party will be constantly harried if they try to rest. Something will come along to disturb the rest.

6) If the party retreats beyond the 1 mile lair radius, the dragon will send some followers to harry them further, forcing them back to the nearest town if they really want to rest and allowing the dragon to reset and enhance their defences.

The only path to success for the party is appearing weak enough for the dragon to win at the end while still having the ability to beat the dragon when the time comes. If the party is too strong, the dragon retreats. If they are too weak, the dragon crushes them and takes some prisoners.

The party is dealing with a cunning, wily, extremely intelligent opponent who will use whatever tactics needed to win and will enjoy crushing the party while leaving at least one alive to spread the word about the deadly danger represented by the dragon. The dragon will fight to WIN and will make sure that any character that goes down will stay down, they will only try to subdue the last one or two once victory is assured.

[da newt]

The hobgoblins should be very good at evaluating the party's strength / effectiveness - why bother relying on squirrels or kobolds when you have martial experts?

I'd alter Keravath's suggestion to focus on downing one PC and switch it up to capturing one PC - the dragonborn. It will make the stakes really high for the party, is in character of a green, and forces a rescue mission (great for advancing the plot).

Maybe something like - a group of Kobolds attack in the middle of the night, but this is just a distraction for the goblinoid strike team whose soul mission is to capture the dragon born and take them to the green. With a stealthy team of Goblins, Hobgoblins, and Bugbears focused on ambushing just the one PC while everyone is busy dealing w/ the fog of war that attacks at night (near a green's lair where it should be foggy - reduced visibility), maybe a carriage and horse stashed nearby to haul the hostage away quickly, and maybe even a strafing breath weapon attack from the dark of the night, you could create a pretty epic encounter.

BTW what level are the PCs?

[HoboKnight]

Answers:

@Kane0
Why provoke the party? Also, dragon can observe entire time with rats/birds, given he has Regional effects active.

@Keravath
Posting dragon stats here. Yes, dragon is a spellcaster, but limited to an array of spells he has in the module:

Valturnax, Adult Green Dragon
in lair (variant spellcaster
rules, MM)
HP: 207 AC: 19
Speed: 40’, fly 80’, swim 40’
STR +6 DEX +1 CON +5
INT +4 WIS +2 CHA +3
CR 15, 13,000 XP or if using
lair actions: 16, 15,000 xp; huge
dragon, lawful evil
Saves: Dex+6, Con+10, Wis+7,
Cha+8
Skills: Deception+8, Insight+7,
Perception +12, Persuasion+8,
Stealth+6
Immunities: poison, poisoned
Passive perception 22
Blindsight 60’, Darkvision 120’
Amphibious: can breathe
water or air
Legendary Resistance
(3/day): If fail saving throw,
can choose to succeed instead
Innate Spellcasting: Spell
save DC 16, spell to hit +8. Can
innately cast the following
spells:
1/day: Mislead, Dispel Magic,
Stinking Cloud
Multi-attack: Can use
Frightful Presence, then make 1
bite attack and 2 claw attacks
Bite: +11, 10’, 17 (2d10+6)
piercing plus 7 (2d6) poison
Claw: +11, 5’, 13 (2d6+6)
slashing
Tail: +11, 15’, 15 (2d8+6)
bludgeoning
Frightful Presence: all of
choice w/in 120’ and aware of
it, DC16 wis save, frightened for
1 minute on fail, can repeat at
end of each turns; on save,
immune for 24 hours
Poison Breath (Recharge
5-6): 60’ cone, DC18 Con save,
56 (16d6) poison damage or
half on successful save
Legendary Actions
3/round, recharge at beginning
of Valturnax’s turn
Detect: Wisdom (perception)
check
Tail Attack: Tail Attack
Wing Attack [2 actions]:
Beats wings, all w/in 10’ of
dragon, DC19 Dex save or take
13 (2d6+6) bludgeoning and be
knocked prone; dragon can
then fly 40’
Cast Spell [2 actions]: Can
cast a spell
Lair Actions
On initiative count 20, losing
ties
Grasping Roots: roots and
vines erupt in a 20’ radius w/in
120’, ground becomes difficult
terrain, each creature DC 15
Strength saving throw or be
restrained; can try to free self or
others can try to free with a DC
15 Strength check; disappears
when dragon uses this again or
dies
Wall of Thorns: wall of
thorns, 60’ long, 10’ high, 5’
thick, within 120’ of dragon,
when it appears all w/in wall’s
area must make a DC15 Dex
save or take 18 (4d8) piercing
and pushed to one side of its
choice. Moving through the
wall takes 4x as much
movement as normal and DC 15
Dex or take 18 (4d8) damage.
Each 10’ section has AC 5, 15
hp, vulnerability to fire,
resistance to bludgeoning and
piercing, and immunity to
psychic; wall sinks into ground
when dragon uses this again or
dragon dies
Magic Fog: Magical fog
billows around one creature
w/in 120’ the dragon can see,
creature must make a DC15
Wisdom save or be charmed
until initiative count 20 on the
next round.
Regional Effects
Pass Without a Trace:
Within 1 mile of his lair,
Valturnax leaves no physical
evidence of his passage unless
he wishes to. Tracking him is
impossible except through
magical means. He ignores
movement impediments and
damage from plants in this area
that aren’t magical or creatures.
Plants remove themselves from
his path.
Rodent Eyes and Ears:
Rodents and birds within 1 mile
of Valturnax’s lair serve as his
eyes and ears. Deer and large
game are strangely absent,
hinting at the presence of an
unnaturally hungry predator. If
Valturnax dies, the rodents and
birds lose their supernatural
link to him.


Also: Advenurers don't look stupid, but seasoned.

"What are the dragons goals and objectives? Is the dragon over confident? Have any other dragons been killed recently? Dragons can live a very long time. Although only some have a disposition to be patient, a green dragon often likes to use misdirection and trickery to achieve its goals and they can't achieve those goals when dead."

Dragon was recently chased out of his old lair by his sister. He is here to lick his wounds(no wounds, just pride), amass power and strike backs. No, not over confident.


As I see the statblock, this specific dragon can not create hedges in 1 mile area, but I've added them anyway. Also, no fog, not even in basic adult green 5e statblock.

Ordered focus fire for his minions is a great idea. Retargeting downed characters is also a great idea.

PCs are approaching, they will be at the entrance in a matter of hours.(i failed the 1-mile affected area rule too :D).

A strafing strike at night is a good idea, but... everyone says dragon is too careful to do that. :D

I'm not giving out the party level, since dragon does not know it too. But I can give more visual info on the party, if interested, since he can observe via his rats/birds.

[Kane0]

@Kane0
Why provoke the party? Also, dragon can observe entire time with rats/birds, given he has Regional effects active.


To assess their strength and tactics, and weaken them for a proper followup strike. Once the dragon knows what they can do and how they fight, he can arrange the correct forces to counteract that, hopefully while they are resting or have at least spent resources from the hobgoblin/goblin fight.
The dragon doesnt want to lose more resources than he needs to in order to secure victory, throwing waves and waves of minions or goving up the initiative by going on the defensive is going to pile up the diminishing returns.

Theres a real chance the adventurers might actually be able to be directed against his sister, if he plays his deceptions right. But always have a plan B.

[Kurt Kurageous]

Why not have the party on the bridge, and make the end of the bridge on the dragon's side collapsible with a flick of the tail? It's child's play for the dragon to fix it later with flight and minions, and a tidy way to reduce the number of foes.

Getting the party on to the bridge is another matter, but I would have the dragon argue it as a matter of proving intentions and establishing trust. The dragon doesn't trust the adventurers. If they do not wish the dragon harm, let them prove it. Otherwise, the dragon will assume ill will on the part of the party and act accordingly. It might even tell them so.

[Keravath]

Answers:

@Keravath
Posting dragon stats here. Yes, dragon is a spellcaster, but limited to an array of spells he has in the module:

Valturnax, Adult Green Dragon
in lair (variant spellcaster rules, MM)
HP: 207 AC: 19
Speed: 40’, fly 80’, swim 40’
STR +6 DEX +1 CON +5 INT +4 WIS +2 CHA +3
CR 15, 13,000 XP or if using lair actions: 16, 15,000 xp; huge dragon, lawful evil
Saves: Dex+6, Con+10, Wis+7, Cha+8
Skills: Deception+8, Insight+7, Perception +12, Persuasion+8, Stealth+6
Immunities: poison, poisoned
Passive perception 22
Blindsight 60’, Darkvision 120’
Amphibious: can breathe water or air
Legendary Resistance (3/day): If fail saving throw, can choose to succeed instead
Innate Spellcasting: Spell save DC 16, spell to hit +8. Can innately cast the following spells: 1/day: Mislead, Dispel Magic, Stinking Cloud
Multi-attack: Can use Frightful Presence, then make 1 bite attack and 2 claw attacks
Bite: +11, 10’, 17 (2d10+6) piercing plus 7 (2d6) poison
Claw: +11, 5’, 13 (2d6+6) slashing
Tail: +11, 15’, 15 (2d8+6) bludgeoning
Frightful Presence: all of choice w/in 120’ and aware of it, DC16 wis save, frightened for 1 minute on fail, can repeat at end of each turns; on save, immune for 24 hours
Poison Breath (Recharge 5-6): 60’ cone, DC18 Con save, 56 (16d6) poison damage or half on successful save
Legendary Actions 3/round, recharge at beginning of Valturnax’s turn
Detect: Wisdom (perception) check
Tail Attack: Tail Attack
Wing Attack [2 actions]: Beats wings, all w/in 10’ of dragon, DC19 Dex save or take 13 (2d6+6) bludgeoning and be knocked prone; dragon can then fly 40’
Cast Spell [2 actions]: Can cast a spell
Lair Actions
On initiative count 20, losing ties
Grasping Roots: roots and vines erupt in a 20’ radius w/in 120’, ground becomes difficult terrain, each creature DC 15 Strength saving throw or be restrained; can try to free self or others can try to free with a DC 15 Strength check; disappears when dragon uses this again or dies
Wall of Thorns: wall of thorns, 60’ long, 10’ high, 5’ thick, within 120’ of dragon, when it appears all w/in wall’s area must make a DC15 Dex save or take 18 (4d8) piercing and pushed to one side of its choice. Moving through the wall takes 4x as much movement as normal and DC 15 Dex or take 18 (4d8) damage. Each 10’ section has AC 5, 15 hp, vulnerability to fire, resistance to bludgeoning and piercing, and immunity to psychic; wall sinks into ground when dragon uses this again or dragon dies
Magic Fog: Magical fog billows around one creature w/in 120’ the dragon can see, creature must make a DC15 Wisdom save or be charmed until initiative count 20 on the next round.
Regional Effects
Pass Without a Trace:
Within 1 mile of his lair, Valturnax leaves no physical evidence of his passage unless he wishes to. Tracking him is impossible except through magical means. He ignores movement impediments and damage from plants in this area that aren’t magical or creatures. Plants remove themselves from his path.
Rodent Eyes and Ears:
Rodents and birds within 1 mile of Valturnax’s lair serve as his eyes and ears. Deer and large game are strangely absent, hinting at the presence of an unnaturally hungry predator. If Valturnax dies, the rodents and birds lose their supernatural link to him.


Also: Advenurers don't look stupid, but seasoned.

"What are the dragons goals and objectives? Is the dragon over confident? Have any other dragons been killed recently? Dragons can live a very long time. Although only some have a disposition to be patient, a green dragon often likes to use misdirection and trickery to achieve its goals and they can't achieve those goals when dead."

Dragon was recently chased out of his old lair by his sister. He is here to lick his wounds(no wounds, just pride), amass power and strike backs. No, not over confident.

As I see the statblock, this specific dragon can not create hedges in 1 mile area, but I've added them anyway. Also, no fog, not even in basic adult green 5e statblock.

Ordered focus fire for his minions is a great idea. Retargeting downed characters is also a great idea.

PCs are approaching, they will be at the entrance in a matter of hours.(i failed the 1-mile affected area rule too :D).

A strafing strike at night is a good idea, but... everyone says dragon is too careful to do that. :D

I'm not giving out the party level, since dragon does not know it too. But I can give more visual info on the party, if interested, since he can observe via his rats/birds.

The thicket effect within a mile from the lair is from the Monster Manual but it might not be listed in whatever source you are using for the dragon stat block.

Under Regional Effects for a Green Dragon lair in the Monster manual:

"Regional Effects

The region containing a legendary green dragon’s lair is warped by the dragon’s magic, which creates one or more of the following effects:


Thickets form labyrinthine passages within 1 mile of the dragon’s lair. The thickets act as 10-foot-high, 10-foot-thick walls that block line of sight. Creatures can move through the thickets, with every 1 foot a creature moves costing it 4 feet of movement. A creature in the thickets must make a DC 15 Dexterity saving throw once each round it’s in contact with the thickets or take 3 (1d6) piercing damage from thorns. Each 10-foot-cube of thickets has AC 5, 30 hit points, resistance to bludgeoning and piercing damage, vulnerability to fire damage, and immunity to psychic and thunder damage.
Within 1 mile of its lair, the dragon leaves no physical evidence of its passage unless it wishes to. Tracking it there is impossible except by magical means. In addition, it ignores movement impediments and damage from plants in this area that are neither magical nor creatures, including the thickets described above. The plants remove themselves from the dragon’s path.
Rodents and birds within 1 mile of the dragon’s lair serve as the dragon’s eyes and ears. Deer and other large game are strangely absent, hinting at the presence of an unnaturally hungry predator.


If the dragon dies, the rodents and birds lose their supernatural link to it. The thickets remain, but within 1d10 days, they become mundane plants and normal difficult terrain, losing their thorns."

Does the dragon have any more powerful minions than some kobolds/goblins/hobgoblins/bugbears?

The basic strategy would seem to be to attack the party using groups of various size and strength in order to assess their strength then after weakening them a bit, perhaps hit them with a fly-by breath weapon attack while they are distracted by some goblin archers and see how they react to that.

The concern the dragon is likely to have is "What trick do these adventurers have up their sleeve?" Green dragons are very intelligent, devious, prone to trickery and likely on the alert for such tactics being used against them. The dragon would look for signs of invisible or otherwise disguised additional forces or other forces that might be close enough to come to the assistance of the party. The dragon would probably have the little forest minions both listen and particularly smell for unexpected scents in the forest - especially those not near the party since these might indicate the presence of something else accompanying the party. The dragon would be on the lookout for any indication that this is some sort of trap that the party might be baiting them into.

Depending on the backstory with the dragon's sister - could the dragon wonder if these adventurers have been directed to them by their sister intentionally? Perhaps doing her bidding either directly or indirectly? Are there any secret vulnerabilities that perhaps his sister might know and could have revealed to others or which could have been discovered by other means? The dragon would make particular efforts to guard against any such vulnerabilities.

Finally, the green dragon is aware of spells and effects and would know that it would be very unwise to face the party alone. They would likely have several squads of kobolds/goblins/hobgoblins/bugbears as well as 2-3 more powerful minions if he has any for any significant confrontation with the party. The dragon would also have an escape plan. At the very least this could be a scroll of dimension door that they could use to make a last ditch hasty exit (assuming they can't cast dimension door themselves).

[Corran]

Questions
1) How important is it to the dragon to not being forced to flee from the swamp in search of a new home?
2) How easy and fast will it be to relocate all its loot from the swamp to some safe area if it has to flee relatively in a hurry?

Since the dragon has pass without a trace, attacking with a small group for better chances of a more favorable engagement (and I dont mean just surprise, I also mean location and/or timing; eg the party is sleeping, during a storm, when they cross an area where the water deepens, etc) would not be out of the question. You'll have to send your best troops of course, including the dragon. This is obviously very risky if you dont have a good idea about what you are facing, and from what I am reading, the dragon does not enough about the pc's so I dont think the risk is worth it at this time.

Otherwise, it should attack in force. Try to circle them and to hit fast and hard. The dragon has enough troops that the only tactics that matter here are about minimizing casulaties and cutting off the escape routes of as many pc's as possible (to spare yourself any trouble in the future) by for example prioritizing the guy in the robes who is the more likely to be able to teleport and at the same time use AoEs against your numbers. Someone should stay behind to raise an alarm in case this is all a trick to empty the lair so they can streal the shinies. Also, leave a small force behind to be ready to move the loot away in case the battle does not go as planned. Same as above, this is still a potentially bad idea because the dragon is going in blindly. If you can guess their path, choose where your forces will intercept them and send them there ahead of time if you can do it without making too much noise.

Bottom line, if you must, then either use your strongest small group if you can make surprise count. Otherwise, hit with your full force while doing the basics (hit from all sides without stacking your troops too much and prioritize and focus fire).

An equally bad idea is to try and bluff the pc's. Send two low minions to demand tribute to the dragon because they are crossing its domain. Then try for "the dragonborn has to deliver it personally because of this reason, and it's totally not a trap because of that reason". At best the minion might trigger some answers regarding where the pc's are heading (ask indirectly, "master charges one gold per hour in the swamp for groups of adventurers, how long will you be staying?"; or something less silly, but hopefully something that can shed some light as to where the pc's are going).

Unless the dragon has reason to believe the pc's are heading its way, best thing it could do at this point, is to keep it low and start thinking of ways to expand its source of information to the surrounding areas so that it knows who it is that steps into the swamp next time.

But, if it has a way to move all its loot quickly and safely and if this location is not too important to it for some reason, then it can choose to do anything. I'd go with the all out attack since this puts the dragon into a lower risk. Unless there is an excellent opportunity for making the most of a surprise attack, but it would have to really be that good to tempt me to risk the dragon more.

ps: Did the bullywags obtain permission from the dragon for showing tourists around the swamp? Once the pc's are gone, the dragon needs to have a talk with them. There is room for diplomacy obviously (after the dragon sets the score right for the mistake of the two currently leading the party), for a short time they could start guiding adventurers to a trap. Eventually (after the dragon asserts some influence with creatures outside the swamp) it would be best to have them gone though.

[Sigreid]

If I were the dragon, I'd use my minions to target the mounts first as others have said. Next would be the guides, followed by destroying their supplies. The goal would be to have them lost in a hostile swamp with no mounts and no supplies. Send goblins to harass them just enough that nobody gets a good rest. Strike and run away and hide.

Incidentally, mounts should be of limited value in a swamp. I don't know if you've ever been deep in a swamp, but you don't tend to have a lot of large land animals there for a reason.

[Kane0]

Incidentally, mounts should be of limited value in a swamp. I don't know if you've ever been deep in a swamp, but you don't tend to have a lot of large land animals there for a reason.

Well except for Catoblepas.

[Sorinth]

One thing that I'll add is that if there are any other big creatures in the swamp like say a Hydra, or even a Giant Crocodile the dragon could try to us the minions or bribe the guides into leading the players into a fight with that other big creature and observe the party's power level in that way.

Also from Fizban's the dragon would have access to Animal Messenger which could be the way it tries to suborn the guards or lure the players into a trap.