D&D 5E Creating a demonoligist PC

[Nikosandros]

I'm currently preparing a 3-4 session adventure set in the Plane of Elemental Fire. The 4 PCs will be pre-gens and will act as trouble-shooters and protection aboard a vessel that is traveling towards the City of Brass. There will be several complications, but one of the main ones will be a noble efreet intent on sinking the vessel who will send elementals and devils against the ship.

One of the 4 PCs will be secretly a demonologist and a bit more powerful than the rest of the party, who will be around 8th level. The idea is that she'll have to play a balancing act between her high effectiveness - especially against the devils - and not being discovered, since another character is a paladin and the Sultan of the City of Brass hates demons and their servants.

I would like to get some advice on how to create such a character. Considering this is a one-off affair and not an ongoing campaign, I'm highly willing to "fudge" things and give that character ad hoc powers.

 

[Nebulous]

I'm currently preparing a 3-4 session adventure set in the Plane of Elemental Fire. The 4 PCs will be pre-gens and will act as trouble-shooters and protection aboard a vessel that is traveling towards the City of Brass. There will be several complications, but one of the main ones will be a noble efreet intent on sinking the vessel who will send elementals and devils against the ship.

One of the 4 PCs will be secretly a demonologist and a bit more powerful than the rest of the party, who will be around 8th level. The idea is that she'll have to play a balancing act between her high effectiveness - especially against the devils - and not being discovered, since another character is a paladin and the Sultan of the City of Brass hates demons and their servants.

I would like to get some advice on how to create such a character. Considering this is a one-off affair and not an ongoing campaign, I'm highly willing to "fudge" things and give that character ad hoc powers.

Ooh, fun. Since you're not going for balance, then the gloves are off and you can do whatever. My first thought was a warlock with a devilish pact. Any attack against a demon (or a devil, i would have the archdemon/devil be opponents) deals 3d6 extra smite damage to the fiend.

Secondly, the character gets one Get Out of Jail Free card. This is an instantaneous diabolical Resurrection. It will come at a cost however of her eternal soul, but that will be more fun to roleplay anyway. As such, the character has unusual bravado and daring because she knows she'll get brought back.

 

[Zaruthustran]

It does seem like Warlock is the way to go. They already have some good spells for dealing with otherworldly threats, like Banishment, Magic Circle, and Protection From Evil. Maybe give your player a custom spell list (either on the "base" Warlock list or as replacement "patron" spells) with some Paladin spells.

More fudging: the level requirements for some of the binding-related Invocations, like Chains of Carceri.

So how about a Chain pact Warlock, Fiend patron, swap out Fiendish Resilience for Awakened Mind (telepathy is great for secret commands / diplomacy with demons), drop level requirement of Chains of Carceri to whatever level the PC will be, and create a custom Background (Demonoligist) with an appropriate custom Benefit: maybe a couple True Names, or a reputation within the Celestial/Fiend/Elemental community in the style of Constantine.

 

[steeldragons]

Just to make sure we're all on the same page, you want this character to be a Demonologist (knows about/works with Demons)...not a Diabolist (knows about/works with Devils)? If you know there are going to be devils to deal with, wouldn't a Diabolist make more sense?

Either way...a Fiend Pacted Warlock would seem to be a first choice. I would go "Diabolist" and give the character an Ice Devil patron, loads of Ice Spells/Invocations, devils kind of leave her alone/inexplicably go easy on her.

Other option, Conjurer Wizard. Load up on the lightning and ice dealing spells. Protections and banishments for dealing with devils (you can't actually banish fire elementals from the plane of fire, can you?). Benign Transposition is very handy...and would allow the PC to avoid conflicts/"be defending herself" (while not damaging the opposition), seemingly "in the fight" with the others.

As either a Warlock or Wizard, refluff the Conjure Minor Elementals (3rd level conjuration spell) and, if she's 9th level or higher Conjure Elemental (5th level spell), to be Demons/Devils. Keep the same CRs, same spell entirely, just "conjuring" from a different plane of origin to give her the kind of fiends she works with instead of elementals (of course conjuring Water elementals will probably be very useful also).

Demon/Devil worshiping Cleric. Probably the most work. Have to come up with a suitable Domain and powers. Forget that.

Any which way: Demon/devil lore, Deception and Persuasion proficiencies.

I'd give them a Protection Scroll (well, depending on how Protection Scrolls work in 5e. I don't actually know the details) against Fire Elementals and/or one against Devils.

Or, probably simplest, go with any kind of spellcaster you want and create a Demonologist/Diabolist Feat:
Prerequisite: Intelligence or Wisdom of 13 or higher and the ability to cast spells.
- Gain Abyssal or Infernal, respectively (if indeed these are separate languages in 5e), as a bonus language
- You have advantage on all Charisma rolls (interactions, saves, etc...) when dealing with demons or devils, respectively.
- When casting a spell that conjures or otherwise effects a specific type of extraplanar being, the Demonologist/Diabolist can make an Intelligence [Arcana] roll to substitute the spell's creature type with a demon(s) or devil(s), respectively, matching the spell's specifications.

 

[Zaruthustran]

The more I think about it, the more I think it might be fun to go with a non-Warlock. Give the PC the Find Familiar spell, and the demon familiar (Quasit). The demon is the demonoligist's personal connection with his favored subject.

This way the PC can be whatever class is needed for party balance. The Quasit can take a mundane form and thereby be assumed to be a typical familiar. The jig will be up the first time the Paladin uses Divine Sense, which will be amusing and will lead to some bargaining by the demonoligist ("this little guy is firmly under my control, don't worry!" Or maybe the Paladin just routinely kills the familiar every chance he gets, forcing the PC to spend an hour and ten minutes (and 10gp in materials) re-summoning.

Combined with the custom Background, and perhaps Steel Dragons's feat, you've got a demonoligist who can be any class. Monk would be an interesting choice.

 

[steeldragons]

Also noting this will be a character over 8th level, if you go with my Feat idea, round out the character with the Elemental Adept as their second [8th level?] Feat. Turning any of your damage spells into ice/cold damage on the elemental plane of fire seems like a REALLY good idea.

To riff off Zaruthustran's idea for a minute, an Eldritch Knight Fighter with Demonologist/Diabolist [4th] and Elemental Adept [8th] sounds like it would be kick-ASS in this adventure. Now I wanna play one!

 

[Zaruthustran]

Yeah, Eldritch Knight or Arcane Trickster both seem like a good fit/twist. If this guy is a covert demonoligist, it seems like playing an overt caster would be less fun than playing a fighter or rogue who can pass off his magical knowledge as simply having "picked up some tricks."

 

[Nikosandros]

Just to make sure we're all on the same page, you want this character to be a Demonologist (knows about/works with Demons)...not a Diabolist (knows about/works with Devils)? If you know there are going to be devils to deal with, wouldn't a Diabolist make more sense

The character is a servant of demons and thus she hates devils and her masters have provided her with the means to hurt her enemies.

 

[Nikosandros]

Thanks for all the advice. I'll go with a warlock or some warlock/wizard combination, since an arcane caster is kind of necessary in the adventure.