First Boss Monster Build - All Help Welcome!

[Trit One-Ear]

Hey all,

My players are reaching a big chapter-conclusion fight next session, and I've been building a special monster for the occasion. This is my first time building my own monsters in 5th Ed, and in many ways the first time running a big single-boss monster fight. As such I'd love some insight and advice before this weekend's session.
Without getting too deep into the story, they are poised to fight a drow mage that has siphoned the power from a chromatic dragon. As such, I've mainly based the physical stats off a green dragon (figuring its clever nature made it a good choice for a sly, manipulative drow) and the mental stats off the drow mage.

Right now it feels really... busy. The spell-casting trait is the one I feel will be least likely to come into play, thought throwing out a nasty insect plague might come in handy. Please let me know if there are any major blunders, or even just things you feel would be better changed!

Party composition: 6 PC's, all 7th level (might include their 3rd level Ranger guide in the final fight)
Goliath Barbarian (Ancestral Guardian)
Human Bard (College of Valor)
Human Cleric (Tempest Domain)
Dragonborn Rogue (Thief Archetype)
Halfling Sorcerer (Wild Magic)
Human Wizard (UA Loremaster School)


- Trit

Drow-Dragon Hybrid
Huge dragon fey, neutral evil
Armor Class: 18 (natural armor)
Hit Points: 242 (21d12 + 105) (effective 302)
Speed: 40 ft., fly 60 ft., climb 40 ft.


STR: 20 (+5) DEX: 16 (+3) CON: 20 (+5)
INT: 13 (+1) WIS: 18 (+4) CHA: 18 (+4)


Saving Throws: Dex +7, Con: +9, Wix +8, Cha +8


Skills: Insight +7, Perception +7, Religion + 5, Stealth + 7


Damage Immunities: See Chromatic Adaptation for details.
Condition Immunities: See Chromatic Adaptation for details.
Senses: Darkvision 120 ft., passive Perception 17
Languages: Common, Elven, Undercommon
Challenge: CR 12 (8,400 xp)




Chromatic Adaptation: At the start of the hybrid's turn, roll a d6. The hybrid takes on aspects of a color of dragon, based on the result of the roll. The hybrid has these traits until the beginning of her next turn. Consult the following table:


[TABLE="width: 500"]
[TR]
[TD]d6 result[/TD]
[TD]Color(s)[/TD]
[TD]Resistances/Immunities[/TD]
[TD]Breath weapon[/TD]
[/TR]
[TR]
[TD]1[/TD]
[TD]Black or Copper[/TD]
[TD]Immunity: Acid[/TD]
[TD]Acid, 5 by 60 ft line. (Dex save)[/TD]
[/TR]
[TR]
[TD]2[/TD]
[TD]Blue or Bronze[/TD]
[TD]Immunity: Lightning[/TD]
[TD]Lightning, 5 by 60 ft line. (Dex save)[/TD]
[/TR]
[TR]
[TD]3[/TD]
[TD]Brass or Red[/TD]
[TD]Immunity: Fire[/TD]
[TD]Fire, 60 ft. cone (Dex save)[/TD]
[/TR]
[TR]
[TD]4[/TD]
[TD]Green[/TD]
[TD]Immunity: Poison, Poisoned condition[/TD]
[TD]Poison, 60 ft. cone (Con save)[/TD]
[/TR]
[TR]
[TD]5[/TD]
[TD]Silver or White[/TD]
[TD]Immunity: Cold [/TD]
[TD]Cold, 60 ft. cone (Con save)[/TD]
[/TR]
[TR]
[TD]6[/TD]
[TD]Chromatic[/TD]
[TD]Resistance: Bludgeoning, slashing and piercing from nonmagical weapons.[/TD]
[TD]None.[/TD]
[/TR]
[/TABLE]


Fey Ancestry: The hybrid has advantage on saving throws against being charmed, and magic can't put it to sleep.


Innate Spellcasting: The hybrid's innate spellcasting ability is Charisma (spells save DC 16). She can innately cast the following spells, requiring no materiel components:
At will: dancing lights
1/day each: darkness, faerie fire, levitate (self only)


Legendary Resistance (3/day): If the hybrid fails a saving throw, it can choose to succeed instead.


Spellcasting: The hybrid is a 10th-level spellcaster. Her spellcasting ability is Wisdom (save DC 16, +8 to hit with spell attacks). The hybrid has the following cleric spells prepared:
Cantrips (at will): guidance, poison spray, resistance, spare the dying, thaumaturgy
1^st level (4 slots): animal frienship, cure wounds, detect poison and disease, ray of sickness
2^nd level (3 slots): lesser restoration, protection from poison, web
3^rd level (3 slots): conjure animals (2 giant spiders), dispel magic
4^th level (3 slots): divination, freedom of movement
5^th level (2 slots): insect plague, mass cure wounds


Spiderclimb: The hybrid can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.


Sunlight Sensitivity: While in sunlight, the hybrid has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.


Web Walker: The hybrid ignores movement restrictions caused by webbing.


Actions


Multiattack: The hybrid makes three attacks: one with its bite and two with its claws. Alternatively it can attack with its bite and cast one spell.


Bite: Melee Weapon attack: +8 to hit, reach 10ft, one target.
Hit: 2d10 + 5 (16) piercing damage.


Claw: Melee Weapon attack: +8 to hit, reach 5ft., one target.
Hit: 2d6 + 5 (12) slashing damage.


Tail: Melee Weapon attack: +8 to hit, reach 15ft., one target.
Hit: 2d8 + 5 (14) bludgeoning damage.


Breath Weapon (Recharge 5-6): The dragon exhales a dangerous breath weapon. See Chromatic Adaptation for details concerning area shape, save required and damage type. Each creature in the area must make the listed save (DC 17) or take 38 (11d6) damage of the given damage type, or half as much damage on a successful save.


Legendary Actions
The hybrid can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time, and only at the end of another creature's turn. The hybrid rregains spent legendary actions at the start of its turn.


Decect: The hybrid makes a Wisdom (Perception) check.
Cast a Spell (Costs 1-3 actions): The hybrid expends a spell slot to cast a 1st-, 2nd-, or 3rd-level spell that she has prepared. Doing so costs 1 legendary action per level of the spell.
Tail Attack: The hybrid makes a tail attack.
Wing Attack (Costs 2 actions): The hybrid beats its wings. Each creature within 10 feet of the hybrid must succeed a DC 18 Dexterity saving throw or take 13 (2d6+6) bludgeoning damage and be knocked prone. The hybrid can fly up to half its flying speed.

 

[Bawylie]

I don’t know about the campaign, so forgive any bad assumptions on my part.

That said, this baddie feels a bit more like a pile of stuff than a cool fusion of drow-gon.

I think if I were writing it up, I might do it as three separate stat blocks, each representing a phase/form of the encounter.

For phase one, I think I’d have the drow priestess of Lloth from the monster manual with maximum HP and damage (this is a boss, after all). I’d put her in a green scale skin dress and give her the poison breath from the young green dragon in place of the demon summoning. Phase one would end when her HP was depleted. Credit to theangryGM here but also at the end of this phase, any lingering effects should wear off automatically at this point.

For phase two, I’d have her change forms to an adult green dragon (again, max HP, max damage values). She should retain the sunlight sensitivity and fey ancestry, but should otherwise fight like a green dragon this phase. And this phase also should end once the HP are completely depleted.

For the final phase, I’d have a hybrid of the two. I’m aiming for CR 8 here but I’m not fussy if I overshoot. I think 17 AC, the physical stats from the green dragon, the mental stats from the drow priestess, wings and a tail, legendary actions from the legendary green dragon, a three hit multi attack split between the scourge and a bite, the dragon breath, and probably 2 or 3 signature spells. Something like 175 - 200 HP.

For spells, I like stuff that messes with players and increases mobility. Since I’m suggesting max damage, it’s prudent to spread it around among the adventurers. So I’d have expeditious retreat, hold person, invisibility, and dimension door. That’ll keep her moving in phases where she can cast spells. Darkness and Fear make good options for this baddie too.

All told we end up with 3 sequential encounters at CR 8 each. If that’s not tough enough, I recommend giving your baddie two separate full turns in phase 2 and three turns in phase 3. But it might not be necessary depending on your party’s composition and power level, the effectiveness of the legendary actions, etc. lots of people plan this stuff out and I do too, but I also like to keep my options open.

Should be a fun little fight. I’d have some environment design here too to take advantage of some drow-gon features. Trees, water, heights, depths, darkness, stuff like that.

 

[dave2008]

I think this looks like a good start, but it is really hard to evaluate without at least know what level your part is. The mix of classes would be more helpful. However, two things that jump out are:

1) It will definitely need proficiency in some saving throws.
2) It needs some off turn movement besides wing attack (most likely)

 

[Trit One-Ear]

I think this looks like a good start, but it is really hard to evaluate without at least know what level your part is. The mix of classes would be more helpful. However, two things that jump out are:

1) It will definitely need proficiency in some saving throws.
2) It needs some off turn movement besides wing attack (most likely)

Meant to add party make-up to the original post. My bad! Edited above.
Definitely forgot to give it saving throw proficiencies as well, also edited above!

Trit

 

[77IM]

I like this monster's design, but against 6 level-7 PCs in a straight-up fight, I predict it getting absolutely thrashed.

Things I think will work well:
- Chromatic adaption is a really cool way to keep this fight dynamic. Make sure you telegraph this ability -- every time hybrid shifts, its color should change, or something.
- Bite + Spell is a pretty good multiattack routine and may make up for the lack of Frightful Presence. (In most big dragon fights, they hit some PCs with fear in the first round or two, which can really give the dragon an edge early-on, and can also feel dynamic when the fear wears off and all the melee people can close in.)
- Legendary spell casting is great. I'm going to steal this.
- Webwalker: if the hybrid is in a place that is actually full of webs, this is amazing. The boss can fly right through a wall of webbing that the PCs might need to make checks or spend actions to penetrate.

Things that I'd change:
- Breath weapon damage is super low. Even a CR 8 young green dragon deals 42 damage, and this thing is CR 12. The thing about dragons is that their weapon attacks are sub-par for their CR, but their breath weapons are scary as . I'd increase the breath damage by probably 25-50%. That may be enough to one-shot the squishies in your party, but that's kind of the point. The PCs should be spreading out to avoid having more than two of them caught in a breath attack.
- Spell list is a bit lackluster. Fill it with spells that you could imagine the boss actually wanting to cast. Defensive spells such as mirror image and greater invisibility and fire shield can work wonders. At your level, counterspell is a must-have.
- Movement is too low. Dragons are amazing boss enemies when they can do hit-and-run tactics, particularly in an environment that gives them lots of cover and concealment. Consider adding misty step spell, as it's a bonus action to cast. Terrain that slows the PCs is also helpful (cliffs, pits, pools of water, WEBBING). The reason hit-and-run is so effective is the breath weapon recharge, and it's especially synergistic with spellcasting: when the breath weapon is recharging, the hybrid hides and spends a round or two casting defensive and buff spells on itself, or summoning spiders or something. Hiding and casting cure wounds using legendary actions may also be a good idea, especially if the PCs have taken a beating and need a round or two to recover, also.

Things that I'd think about ahead of time:
- Consider lair actions. These are fun, and are usually low-damage effects that serve more as battlefield control and can make the environment seem more dynamic.
- One way to make a fight seem more dynamic, especially on a boss with decent hit points, is to have them change tactics mid-fight. Maybe she starts with breath weapons and offensive spells, but after a round or two, summons monsters and then retreats to hide and heal and buff, and comes back as a skirmisher. When the hit points are low, she engages the back line in melee. Monster tactics are also a good way to adjust the encounter's difficulty on-the-fly.
- Think about what will happen if the PCs lose. Would it just be the end of the campaign? Would they be taken captive? Left for dead? There's no wrong answer.
- Think about how to adjust the difficulty on-the-fly. A good boss fight has the players thinking "well, it was a fun ride, but I guess this is it" but then they win at the last minute. Monster tactics are a good way to do this; if the party is getting pummeled, have the boss get overconfident and play stupid. Spell use and magic item use can also affect difficulty -- if things are too easy, have the boss retreat and quaff some potions of superior healing, after using some high-level summoning items. The easiest thing to adjust difficulty is to fudge the boss's hit points. E.g., if the fight is too hard, and there's only one PC left and they make a suicidal leap at the boss and hit, the boss dies in dramatic agony (turns out they only had a few HP left). You can also fudge the hit points to drag out the fight if it feels over too quickly. I don't generally like doing this because it feels like "cheating." But monster math is hard and if your difficulty prediction was waaaay off, then that's an honest mistake, and you can correct it on-the-fly.

 

[dave2008]

Meant to add party make-up to the original post. My bad! Edited above.
Definitely forgot to give it saving throw proficiencies as well, also edited above!

Trit

OK with 6 PCs, and a lot of magic users to boot, I think this guy is going to need to be seriously beefed up. They probably take it out in 2 rounds, 3 rounds max. with little worry. I generally like my boss fights to last 5+ rounds.

Some additional suggestions:

1) add magic resistance or something similar. With so many magic using classes they will chew through legendary resistance in no time.
2) more hit points, maybe max HP? Though adding magic resistance might be enough.
3) More damage (EDIT: I see you beefed up breath weapons - that helps, but probably not enough)

 

[Quickleaf]

[MENTION=6678017]Trit One-Ear[/MENTION] Hey, good to see you homebrewing on ENWorld again!

Three quick questions for clarity:

(1) The creature is a drow who absorbed a dragon's life force and it's Huge. With your narrative, I'd assumed it would be a normal Medium-sized drow. Why is it Huge? Should we a picture a towering Drow giant with draconic eyes and wings...a "drider" with a dragon's lower torso and upper torso of a drow...a purple-colored dragon...or what?

(2) If the drow drained a, say, green dragon, why does it have the Chromatic Adaptation trait? It's a cool trait, I'm just not following how you arrived at that from the narrative. And clearly this is a monster for whom the narrative is important!

(3) You say "drow mage", but the monster's spellcasting is that of a "drow priestess of lolth". Which do you mean?

Once I know those answers I can offer more specific advice, but right away I do see a couple changes you can make to clean up the stat block:

• Fly speed and levitation are redundant. I'd get rid of levitation.
• It's probably not going to be casting dancing lights, and that's the sort of thing that you could easily incorporate into regional effects or lair actions. I'd get rid of dancing lights. And I'd also be tempted to merge faerie fire into a lair action, allowing me to get rid of faerie fire too.
• With the goal of removing all innate spells (to ease the burden on the DM running the monster), I'd replace darkness with some kind of shadowy aura the monster can opt to activate. Auras are also a great way to buff up a solo monsters facing a large well-armed PC party. You might tie the specific effects of the aura into its Chromatic Adaptation. Or you could have the aura give the monster something to do with its bonus action or reaction.
• I'd consider upgrading its Fey Ancestry to outright immunity to charmed & sleep. Helps reduce clutter in an already complicated stat block.

 

[Trit One-Ear]

Hey all,

My session got pushed back 2 weeks so I've been lax in responding. Thank you all for the very helpful responses!
Some additional context for those who were asking:
An ancient dragon has been beneath this city for generations, kept in a magical slumber by an enchantment. Its very presence radiates magic, making the city hot spot for magical experiments and studies. Every 15 years the dragon must be enchanted again, lest it wake and destroy the city. One of the PC's is central to the ritual to keep the dragon slumbering, and when he was MIA (long story), the drow swept in to "save" the city. The cast their own ritual to keep the dragon slumbering, but secretly it siphons its strength into a magical amulet. When it dons this amulet (which it will do during the boss fight) it will gain the "power" of the dragon. I've imagined this as not only gaining the dragon's abilities but also many physical traits. I'm also picturing some good ol' drider traits, as this drow is one of Lolth's chosen.

I'm particularly interested in [MENTION=6776133]Bawylie[/MENTION]'s 3-stage set up. It sounds very dynamic, cleaner to run, and easier to fudge the difficultly at each stage. Starting with the Drow Priestess of Lolth (probably with 2 drow elite warriors as support), wearing the necklace. I'd replace the demon summoning with a lesser version of the Chromatic Adaptation, with just the breath weapon.
When she's defeated, the power of the amulet will surge through her, animating her as an avatar of the dragon. I think an Adult Green Dragon for the stats makes sense, giving it a more skirmisher feel, probably keeping the chromatic adaptation trait running. I'd start adding lair actions here. When he's defeated this way, the power will erupt fully, violently transforming her into a beastial dragon-drider hybrid.
Lastly, I'll draft up a different version of the stat block above, set at CR 8 or 9, with a more intentional selection of spells and attacks. Physical stats of an adult green dragon, mental stats of the drow priestess, full lair actions, and probably some transformation of the terrain (webs explode, rifts in the floor etc.)
I'll try and get a draft of the new hybrid stats up soon!

Trit

 

[Trit One-Ear]

Hi all,

Finally had a little time to whip together the new stat block. It's very similar to the old, but I changed the math a bit (bringing it more in line to the new CR 8), and changed the spell list based on advice given above. It feels a lot more focused now, even if it's not too greatly changed. Bearing in mind that it's the third stage of the fight, I did eliminate a few things that would make it feel too similar. Other differences will be lair based, and change dynamically between stages of the fight.
As always, very grateful for input and advice.

Drow Dragon Hybrid (Stage 3)


CR 8
Prof Bonus +3
AC 17
HP 200
Attack +7
Damage/Round 51 - 56
Save DC 16

Drow-Dragon Hybrid
Huge dragon fey, neutral evil
Armor Class: 17 (natural armor)
Hit Points: 204 (15d12 + 24)
Speed: 40 ft., fly 60 ft., climb 40 ft.

STR: 19 (+4) DEX: 11 (+1) CON: 17 (+3)
INT: 13 (+1) WIS: 17 (+3) CHA: 18 (+4)

Saving Throws: Dex: +4, Con: + 6, Wis: +6, Cha: +7

Skills: Insight +6, Perception +6, Religion + 4, Stealth +4

Damage Immunities: See Chromatic Adaptation for details.
Condition Immunities: See Chromatic Adaptation for details.
Senses: Darkvision 120 ft., passive Perception 16
Languages: Common, Elven, Undercommon
Challenge: CR 8 (3,900 xp)

Chromatic Adaptation: At the start of the hybrid's turn, roll a d6. The hybrid takes on aspects of a color of dragon, based on the result of the roll. The hybrid has these traits until the beginning of her next turn. Consult the following table:

d6 result
Color(s)
Resistances/Immunities
Breath weapon
1
Black or Copper
Immunity: Acid
Acid, 5 by 60 ft line. (Dex save)
2
Blue or Bronze
Immunity: Lightning
Lightning, 5 by 60 ft line. (Dex save)
3
Brass or Red
Immunity: Fire
Fire, 60 ft. cone (Dex save)
4
Green
Immunity: Poison, Poisoned condition
Poison, 60 ft. cone (Con save)
5
Silver or White
Immunity: Cold
Cold, 60 ft. cone (Con Save)
6
Chromatic
Resistance: Bludgeoning, slashing and piercing from nonmagical weapons.
None.


Fey Ancestry: The hybrid is immune to being charmed, and magic can't put it to sleep.

Legendary Resistance (3/day): If the hybrid fails a saving throw, it can choose to succeed instead.

Spellcasting: The hybrid is a 10th-level spellcaster. Her spellcasting ability is Wisdom (save DC 15, +7 to hit with spell attacks). The hybrid has the following cleric spells prepared:
Cantrips (at will): poison spray, resistance
1st level (4 slots): cure wounds, expeditious retreat, ray of sickness,
2nd level (3 slots): darkness, hold person, lesser restoration, web
3rd level (3 slots): counterspell, dispel magic, fear
4th level (3 slots): dimension door, freedom of movement

Spiderclimb: The hybrid can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Sunlight Sensitivity: While in sunlight, the hybrid has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.

Web Walker: The hybrid ignores movement restrictions caused by webbing.

Actions

Multiattack: The hybrid makes three attacks: one with its bite and two with its claws. Alternatively it can attack with its bite and cast one spell.

Bite: Melee Weapon attack: +7 to hit, reach 10ft, one target.
Hit: 2d10 + 5 (16) piercing damage.

Claw: Melee Weapon attack: +7 to hit, reach 5ft., one target.
Hit: 2d6 + 5 (12) slashing damage.

Tail: Melee Weapon attack: +7 to hit, reach 15ft., one target.
Hit: 2d8 + 5 (14) bludgeoning damage.

Breath Weapon (Recharge 5-6): The dragon exhales a dangerous breath weapon. See Chromatic Adaptation for details concerning area shape, save required and damage type. Each creature in the area must make the listed save (DC 17) or take 42 (12d6) damage of the given damage type, or half as much damage on a successful save.

Legendary Actions
The hybrid can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time, and only at the end of another creature's turn. The hybrid rregains spent legendary actions at the start of its turn.

Decect: The hybrid makes a Wisdom (Perception) check.
Cast a Spell (Costs 1-3 actions): The hybrid expends a spell slot to cast a 1st-, 2nd-, or 3rd-level spell that she has prepared. Doing so costs 1 legendary action per level of the spell.
Tail Attack: The hybrid makes a tail attack.
Wing Attack (Costs 2 actions): The hybrid beats its wings. Each creature within 10 feet of the hybrid must succeed a DC 18 Dexterity saving throw or take 13 (2d6+6) bludgeoning damage and be knocked prone. The hybrid can fly up to half its flying speed.

 

[Wiseblood]

I agree with Bawylie. My first thought was of the Dragonlord from the NES release called Dragon Warrior in the states.

Starts out wizardly then transforms into a dragon during the fight.

Drow form dressed in finery as normal for drow but when hit by damaging spells or weapons a flash of green scales flicker briefly across the exposed skin.

Dragon form I would probably give it a color scheme all their own. Iridescent purple-green with a white sail and scarlet colored eyes.

As far as abilities go I tend to trim it down to the most flexible and potent ones and ditch the rest.

A couple of minor goons to soak some actions from the players.

Followed by a change of venue for the big reveal. A quick dash to another room or something.

But....that’s just where my brain took me.