(D&D 4E) End of Adventure Boss (For use in a campaign)

[Nu]

I'm running a 4th Edition D&D campaign and have been looking to have my party fight a young dragon at the end of an adventure they are about to embark upon. This is intended to be a difficult encounter, and for various reasons none of the dragons presented in the current books work for it.

So, I've decided to work up my own homebrew dragon to have the PCs face off against. It's designed as a hybrid of the catastrophic dragons from the MM3, and the preview of the young black dragon from Essentials. I'm looking for critique before I have the PCs fight it: the expected party level is level 3, and I'll probably add in some quest XP on top of the kill XP to make up for the fact that it's supposed to be a hard fight.

Mostly I'm looking for mechanical feedback, suggestions as to how I could improve or better implement it, and make sure I'm not going to slaughter the party.

Note that I take no credit for originality here. The idea of the monster is a necrotic dragon that transforms into a half-fire-elemental when bloodied. I hope the formatting is all right, I rather like how it turned out as similar to the MM entries. Oh, and the HP was based on using a 3x multiplier rather than the usual 4x for solos.

Young Fell Dragon (Level 4 Solo Brute) 875 XP
Large elemental magical beast (fire, necrotic, dragon)

Initiative +7
Senses Perception +6; Darkvision

HP 172; Bloodied 86
AC 17; Fortitude 18; Reflex 16; Will 17
Saving Throws +5, Action Points 2, Speed 6; fly 6 (clumsy)
Resist 5 necrotic, 5 fire

{table=head]TRAITS

Action Recovery


Whenever the dragon ends its turn, any dazing, stunning, or dominating effect on it ends.


Elemental Core ✦ Aura 1


Each enemy that ends its turn in the aura loses all fire and necrotic resistance until the end of its next turn.


Instinctive Action


The dragon can use a free action to charge or use bite on an initiative of its initiative check - 10. If the dragon cannot use a free action on this initiative count due to a dominating or stunning effect, then that effect ends instead of the dragon making its attack.
[/table]

{table=head]STANDARD ACTIONS

Bite (necrotic) ✦ At-Will


Attack: Basic Melee 2 (one creature) +9 vs. AC
Hit: 2d8 + 4 damage, and ongoing 5 necrotic damage (save ends).
Miss: 5 necrotic damage.


Claw ✦ At-Will


Attack: Melee 2 (one creature) +9 vs. AC. The dragon makes this attack twice, either twice against the same creature or one attack against two different creatures.
Hit: 2d6 + 5 damage.


Shadowflame Breath (fire, necrotic) ✦ Recharge [5] [6]


Attack: Close blast 5 (enemies in blast) +7 vs. Reflex
Hit: 2d8 + 3 necrotic damage, and the target is weakened (save ends).
Miss: Half damage.
Special: If the dragon is bloodied, the blast creates a zone of scorching flames until the end of the dragon's next turn. Each creature that enters or begins its turn in the zone takes 5 fire damage.
[/table]

{table=head]MINOR ACTIONS

Darkening Fire (fire) ✦ Recharge at the start of any turn when elemental core is aura 1


Effect: (The dragon must be bloodied) Elemental core expands to aura 3. At the start of the dragon's next turn, elemental core expands to aura 5. When the dragon uses instinctive action, if it is able to charge or use bite and elemental core is aura 5, it uses the following attack instead.
Attack: Close burst 5 (enemies in burst) +7 vs. Reflex
Hit: Ongoing 5 fire damage and the target is vulnerable 5 necrotic (save ends both).
Miss: 5 fire damage.
Effect: Elemental core reverts to aura 1.
[/table]

{table=head]TRIGGERED ACTIONS

Flail Spike ✦ At-Will


Trigger: An enemy moves into a position where it flanks the dragon.
Attack (Opportunity Action): Melee 3 (triggering enemy) +7 vs. Fortitude
Hit: 1d6 + 2 damage, and the target is pushed 1 square and knocked prone.


Flame Lash (fire) ✦ At-Will


Trigger: The dragon takes damage while bloodied.
Effect (Immediate Reaction): Each creature in the elemental core aura takes 5 fire damage.


Bloodied Breath ✦ Encounter


Trigger: The dragon is first bloodied.
Effect (Free Action): Shadowflame breath recharges, and the dragon uses it.
[/table]

Skills Endurance +10
{table=head]Ability|Score|Modifier|Modifier + 1/2 Level

Strength|
19|
+4|
+6

Constitution|
17|
+3|
+5

Dexterity|
16|
+3|
+5

Intelligence|
13|
+1|
+3

Wisdom|
18|
+4|
+6

Charisma|
16|
+3|
+5
[/table]

[Deathdarken]

this seems really powerful how many players you got playing this I don't think many monsters have a on miss damage. Even with lower HP I don't think that makes up for this. I did a Dark sun game not too long ago I player killed the players. You got to be mindful of power level of monsers

[Chainsaw Hobbit]

What level is the party?
While this looks overpowered, don't underestimate the capability of a 4E party.
They are more difficult to kill than you might expect, and they (especially at higher levels) have more tricks up their sleeve than you would probably think.

However, I am a famous TPK DM and I often have no sense of proportion.

[137beth]

@above: he said the expected party level was 3rd.

In 4e, a large group can be significantly more powerful than you would expect. For an adventure boss, it is okay to have it hard, as long as you are fairly confident that the players can win. Since you are making the monster specifically for this fight, it would be a good idea to play-test it before you use it in-game, preferably with the projected stats and equipment of your party when they reach it. If you expect their magic items to come from treasure parcels you place, then you can have a good sense of their inventory by that point.

[Nu]

The party is six players: a wizard, a warlock, a ranger, a paladin, a warlord, and shaman. Their optimization level is pretty good, and I've given them magical items that currently put them just under the expected magical item threshold for their level (I hope to catch them up before this encounter). I was considering giving them a chance to obtain items with necrotic resistance before this fight, as it can help despite the aura (which only affects characters that end their turn in the aura, which is easier to avoid than one might think). The wizard in particular is very powerful at this level, with an array of illusion/psychic spells that target Will and a magic crystal orb.

I've never actually had them fight a solo by itself before, though. The last time I had them fight an "end of adventure boss," I took a solo and redesigned it to be an encounter with 3 monsters (reduced solo's HP, added some soldiers to defend the solo controller, changed the abilities slightly to be more damaging, etc). It turned out pretty good, they burned every resource they had in order to defeat the boss and there were some close calls with the wizard in the negatives at one point. So I'm a bit nervous.

Do you think the current HP total is good? It's actually 3/4ths of what a solo brute of that level with that Constitution score would normally have, but I prefer encounters that are faster and more dangerous. Hence the dragon's ability to almost certainly get an action or two every turn.

A play test is a good idea, thank you for the suggestion. I'll probably need to write one up later when I have time.

[Chainsaw Hobbit]

Hmmmm, they should have no problem with it.
In fact, I think you should increase the Elemental Core radius to 3 and make Bite a minor action.

[Mando Knight]

In fact, I think you should increase the Elemental Core radius to 3 and make Bite a minor action.

Minor action Bite isn't a good idea: it's already got three attacks per turn at minimum (instinctive action Bite, two claw attacks), an OA flank-spiker, and the breath attack. Given that the party has three melee characters and only two leaders, with one leader being a melee character (unless the Warlord and/or the Ranger are ranged builds), the added melee power isn't needed.

What I don't like is the number of abilities on this thing. Very few Solos pre-Paragon, even pre-Epic have access to so many extra attacks.

[Nu]

What I don't like is the number of abilities on this thing. Very few Solos pre-Paragon, even pre-Epic have access to so many extra attacks.

The idea would be to make the solo feel like a whole encounter unto itself rather than a single monster. The instinctive action trait is based on the instinctive devouring trait from the 4E Essentials young black dragon (a level 4 solo lurker), which gives the dragon extra actions but staggers them somewhat to reduce burst potential.

Edit: Oh, yeah, the ranger and warlord are both melee.