Homebrewing Monsters guidelines?

[Tzi]

It is highly likely I've missed it or simply haven't used the right search terms,

BUT I'm having considerable difficulty finding anything resembling a general rule of thumb or guidelines for Homebrewing monsters. Currently trying to make a low level legendary for the end of a particular dungeon and I'm fairly flummoxed.

Can anyone assist?

[Dralnu]

We don't currently have official guidelines for building monsters. It's likely that this information will be given to us with the DMG.

However, one blogger has been analyzing the monster data and predicting the guidelines for making monsters. He's come up with the CR, size, damage, HP, AC, and traits so far. It should be enough to build monsters:
http://surfarcher.blogspot.ca/

Alternatively, tweak a pre-existing monster to suit your needs.

[DireSickFish]

Yeah I'd find an existing monster and put legendary actions on it. Playing with the HP is a good way to scale monsters too.

[Tzi]

Currently used everything to create this...


"Penny," Moriane Salvani
Medium Undead, Chaotic EvilArmor Class 15*(Studded Leather)
Hit Points72 (12d8+18)
Speed 40 ft

Str
Dex
Con
Int
Wis
Cha


10 (+0)
12 (+1)
16 (+3)
16 (+3)
12 (+1)
18 (+4)

Skills Perception +4, Intimidation +9, Arcane +12
Senses Darkvision 60 ft, passive Perception 12
Damage Resistance*Poison
Condition Immunities*Exhaustion, Poisoned
Languages Kandarian, Abyssal, Sabylian
Challenge 3 (700 XP)

Spellcasting: Penny is a 3rd Level spellcaster with Warlock spells.
(Spell DC 11, +3 to hit)
(Cantrips) Eldritch Blast
(1st) Hex, Witch bolt
(2nd) Mirror Image, Spider Climb

ACTIONS:
Longsword: Melee attack +4, reach 5ft. One target 1d8+1 one hand, 1d10+2 with two hand.

LEGENDARY ACTIONS:
Penny has 3 Legendary Actions to use
Cantrip: Cast another Cantrip spell.
Dissonant Whisper (2 Pt): Cast as Warlock Spell.
Shadow Volley (2 Pt): Deal 2d8 Necrotic damage to all in the room, and targets must make a reflex save, upon failure they are knocked back 15 feet. (DC 14)
Blink (2 pt): Target can teleport anywhere they could stand within 30 feet.
Dark Command (3 pt): One target within 60 ft range must make a will save or become a thrall until after their next turn. (DC 11) If successful, character has disadvantage on all rolls until after their next turn.

REGIONAL ACTIONS:
Cosmic Whisper: The players are besieged by horrible whispers. They must make a will save or be under the effects of a Cosmic Whisper which will put them at a disadvantage on any attack roll in a combat situation or to resist a fear effect.


Overall this a combination of Scholomance bosses from WoW and a Deadite from Evil Dead. Its supposed to be basically someone whom found an Alien tomb of Demonology and evil and has become "The Left Hand of Madness." Setting loose a grizzly plague and a bunch of undead horrors.

Ideally Penny will be a difficult fun boss fight.

[Dralnu]

Hmm. I would think that's higher than CR 3. Using Surf's calculations, CR 3 average is 68hp, 13 AC, 19 damage, ~6th level spellcasting, 2 traits. Penny has higher hp, AC, and damage, but lower spellcasting. The damage is at least ~24 if she does 1 longsword attack + 3 eldritch blasts, which is fine, but way too high if she does shadow volleys. Hex and Mirror Image are also boosts to that damage / defense.

The regional effect seems brutal too. Separate action, everyone that doesn't save has disadvantage for the rest of the fight? Ew.

I'd ditch the regional effect. I'd significantly lower the damage on Shadow Volley. Would probably make "Dark Command" into charmed for 1 turn. Making them into a thrall, but they can still attack you, they just have to avoid attack rolls for a turn? Seems weird. After those nerfs, probably higher than CR 3 still.

[infinitetech]

pretty good, id say it would be about cr 4 but since its all alone not that bad for the party, id say on the passive make it so they re-save each round so that some rounds are good others not, and id say make the shadow volley 3 points, also, if you are willing to make the cr 5, make the command spell apply the undead template to the heroes when taken over(goes away after taken over) and make it stoppable by protection evil, other than that i like it, maybe make a way tho that the heroes can recruit her instead of fight her, if they correctly prepare for the fight, like maybe some hidden items in the dungeon which if used correctly based on wall art will temporarily bind her without her powers and let her talk, she will lose some power until she can get things under control if they recruit her, aka side quest to unlock her potential, also does she have a rare item? would make sense that she would, that way either solution the object exists, the players may grab it or even accidentally use it, and who knows what could happen...

[infinitetech]

pretty good, id say it would be about cr 4 but since its all alone not that bad for the party, id say on the passive make it so they re-save each round so that some rounds are good others not, and id say make the shadow volley 3 points, also, if you are willing to make the cr 5, make the command spell apply the undead template to the heroes when taken over(goes away after taken over) and make it stoppable by protection evil, other than that i like it, maybe make a way tho that the heroes can recruit her instead of fight her, if they correctly prepare for the fight, like maybe some hidden items in the dungeon which if used correctly based on wall art will temporarily bind her without her powers and let her talk, she will lose some power until she can get things under control if they recruit her, aka side quest to unlock her potential, also does she have a rare item? would make sense that she would, that way either solution the object exists, the players may grab it or even accidentally use it, and who knows what could happen...

tell me if you want other ideas, and also can you describe your dungeon?

[Tzi]

pretty good, id say it would be about cr 4 but since its all alone not that bad for the party, id say on the passive make it so they re-save each round so that some rounds are good others not, and id say make the shadow volley 3 points, also, if you are willing to make the cr 5, make the command spell apply the undead template to the heroes when taken over(goes away after taken over) and make it stoppable by protection evil, other than that i like it, maybe make a way tho that the heroes can recruit her instead of fight her, if they correctly prepare for the fight, like maybe some hidden items in the dungeon which if used correctly based on wall art will temporarily bind her without her powers and let her talk, she will lose some power until she can get things under control if they recruit her, aka side quest to unlock her potential, also does she have a rare item? would make sense that she would, that way either solution the object exists, the players may grab it or even accidentally use it, and who knows what could happen...

Actually in the quest, Penny it was discovered was possessed and they knew of a few ways to exorcise the body of the demon/spirit/creature that had latched onto her. They chose to just slog through a fight and incinerate the body afterwards.

When I run another version of this quest I might go with that.

NOTES:

1) The monster was brutally difficult, no player deaths due to lucky rolls BUT most players had single digit HP after the fight, one was knocked out.
2) Actually the shadow volley saved the mob more then a few times by knocking back the fighter.
3) The Regional effect was mainly a one time thing, it hits, you suck during a single mob fight like fighting skeletons or zombies Then it wore off.
4) She did have a rare object, horrible binder/tome made of bronze. With leathery pages latched into it depicting bizarre summoning rituals and at that time unknown rites and incantations.

[infinitetech]

very cool, and sounds like what happens whenever i try to lead a party to a nice, peaceful, intelligent conclusion... "really you actually brought a paper shredder for my plan this time?"

[Tzi]

very cool, and sounds like what happens whenever i try to lead a party to a nice, peaceful, intelligent conclusion... "really you actually brought a paper shredder for my plan this time?"

They survived, they just sort of wished to battle it.

It proved to be a REALLY tough fight though. They defeated the boss actually via destroying the building with a Thunderclap? If I recall correctly. They damaged a wooden pillar and brought down an entire chapel but they did get the cursed Tome. Then afterwards realized they could have avoided their near death.

As an aside, they avoided demonic possession barely.

[infinitetech]

i take it lucky rolls on that last bit, but ive beat bosses that way myself lol