Warlock Patrons: The Fiend

Guide by Sam West, Twitter:@CrierKobold

Diabolism is core to the iconic warlock fantasy. It harkens to the blood sacrifices and pentagrams on the ground found in horror movies and novels. If the classic “deal with the devil” warlock fantasy appeals to you, working with a demonstrably evil monster for ultimate power, the Fiend patron offers you that fantasy alongside all the hellish fire magics you could ask for.

Lots of warlock builds can weaponize the options presented with the Fiend patron, but they may not be abundantly apparent out the gate.

1st-3rd Level: Dark One’s Blessing and 1st and 2nd Expanded Spells

Dark One’s Blessing is the first level feature offered from the fiend patron, and will range between entirely useless on some characters to a robust well of bonus hit points to others. This is the number one feature to push the subclass towards martial options, as getting a tool that gives you a shield of temporary hit points on kills can build you up in the mid tiers as a horde-slaying bulwark. Caster based warlocks get much less out of this feature, as if you aren’t planning on being routinely hit, a refreshing pool of temporary hit points will feel like a bonus you aren’t regularly leveraging in a meaningful way.
Burning Hands is boon to any warlock in the first four levels of the game. It is the best low tier area of effect damaging spell. 3d6-4d6 fire damage in a cone will kill a lot of small critters like kobolds and goblins at once. Melee builds love this early as a tool to deal with overwhelming numbers, nearly guaranteeing temporary hit points with Dark One’s Blessing, and backline caster warlocks will consider positioning up to get a big chunk of damage from behind their frontline allies. I’d highly recommend picking this up for the first four levels, then replacing it with a damaging area upgrade the moment you reach 5th level.
Command is another neat spell to pick up at 1st level that scales really well with Pact Magic spell slots. At 1st level, its short duration makes it something you need to know will have a massive impact to matter, but as 2nd and 3rd level spell, you can regularly get multiple creatures failing the save. This is the first of the backline status effects Fiend offers that will work on control based warlocks. It isn’t something you’ll want to all that regularly break out, but comes with a massive amount of flavor and narrative building moments while also giving you a multi-target action eating option in the low and mid tiers.
Blindness/Deafness is another save or die like Command, this time costing you a 2nd level spell slot for a longer duration effect. Notably, it doesn’t require your concentration, meaning with upper level spell slots you can get multiple creatures blinded at once with this while also concentrating on other effects. Warlocks really care about their concentration, so getting a minute-long duration multi-target crowd control effect without concentration can empower any warlock looking for that. Its impact still isn’t massive, though, and likely isn’t something you’re casting outside of affecting an encounter with an exact number of creatures equal to however many your spell slot currently lets you affect.
Scorching Ray opens up a sweet backline build to Fiendlocks. Paired with Hex, each Scorching Ray you throughout will be dealing 2d6 fire + 1d6 force, and will automatically get up-casted to fire more bolts at 5th, 7th, and 9th level. If you want to be a high single target damaging warlock caster, leveraging Scorching Ray to do a massive burst of damage on builds working with Eldritch Blast can result in a powerful suite of attack based spells that define you as the backline damage battery in the early to mid tiers of play.
With just a 2nd level slot, you can be getting 9d6 damage out of your Scorching Ray + Hex combo, and still have 1d10+1d6 Eldritch Blasts to fall back on for the remainder of Hex’s duration. With up-casts, you’re looking at 12d6-21d6 damage worth of fiery blasts at whatever targets you’d like. It blasts through its resources very quickly, but will hit like a train when it comes together.

4th-7th Level: Dark One’s Own Luck and 3rd and 4th Expanded Spells

Dark One’s Own Luck sets you up at 6th level with a d10 die per short rest to mitigate ability checks and saving throws, acting as a catch-all dice to mitigate disaster. Getting to know the rolled result before adding the d10 makes this an incredibly useful feature that can prevent certain death from a save or die you’d otherwise fail, or turn a 13 Persuasion check you need to succeed into a 15+ fairly consistently. Out of combat, I’d highly encourage liberal use of this; short rests aren’t that difficult to get out of dungeon delving, and it can start to feel quite good to start succeeding on most important ability checks you’re making. It doesn’t work on attack rolls, but short of that, anything you want to pass that you rolled mediocre on Dark One’s Own Luck can bring to success.
Fireball is the most notable spell Fiendlocks get access to I think. Taking this iconically broken high damage area of effect tool and adding it to warlock gives them high impact explosive damage that easily replaces Burning Hands. Getting one to two casts per short rest alongside a long duration concentration effect like Summon Undead will leave you feeling like a powerful backline spellcaster. Even as a Thirsting Blade multi-attack melee warlock, having Fireball in your back pocket to deal with massive amounts of threatening creatures will just feel good. Fireball is one of the reasons to play Fiend warlocks.
Stinking Cloud doesn’t really stand up Fireball, but not much can. As far as 3rd level area control tools go, Stinking Cloud requiring your concentration is a big downside. On top of that, it won’t work in windy environments at all. In cases where you can stick this on a group of creatures to eat a bunch of their actions, you’ll have to ask yourself: was this better than Fireballing them? The answer is nearly always no. It hits the same radius, but instead of killing things, it might eat their actions. To top it off, Stinking Cloud doesn’t even offer an up-cast bonus, meaning it gets considerably worse as your spell slots improve. Most Fiend warlocks don’t want this.
Fire Shield is a spectacular addition to melee fiend builds, adding a 2d8 damage reflection effect that lasts 10 minutes with no concentration requirements. This damage can trigger your Dark One’s Blessing, meaning minions that hit you, then die, may end up netting you hit points, which is sweet. No 5th level up-cast does leave it feeling a bit lackluster in the upper tiers, but if you’re building the martial bloodthirsty devil frontliner, Fire Shield is a great option to have access to. Its duration means you can even occasionally get this to last over two fights, which makes it potentially a way to stretch your limited spell slots a lot further.
Wall of Fire gives the backline warlocks a new toy as well, although this too works great on frontline fiend-locks. If you can get two instances of damage on this consistently, it can be better than Fireball is from a raw damage perspective, but that isn’t necessarily a given. It eating your concentration also makes it a bit tricky to line up alongside the other potent concentration effects. If you want a big wall of sulfurous flames to erupt from hell and blast your enemies, this does that. It probably isn’t consistent enough to regularly cast over Fireball, but can be weaponized to devastating effect in cooperative groups.

8th-10th Level: Fiendish Resilience and 5th Level Expanded Spells

Fiendish Resilience functionally is resistance to bludgeoning, slashing, or piercing damage in 90% of instances, and occasionally will swap to fire or necrotic when delving directly into hell or against a swarm of necromancers. This feature is really boring, but a fine addition to frontline warlocks who now can get a bit more juice out of their hit points. Generally speaking, I’d guess bludgeoning or slashing damage is the most common damage type from an average monster, so I’d probably regularly just pick one of those.
Flame Strike will be a near strict downgrade to Fireball, as the area is a smaller radius on the ground (where most monsters are) and the damage is just 2d6 under what an up-cast Fireball will do. If you REALLY want radiant damage, this is a way to get it, but the vast majority of characters won’t touch this with Fireball at the ready.
Hallow is a nifty little option to consider, though. It’ll feel more like a long form ritual feature you’re getting access to, and seeing as warlocks have so few slots to begin with, getting a spell that doesn’t really care about competing with other spells for spell slots in combat or exploration can be a major boon. Hallow isn’t a wildly powerful effect, nor endlessly applicable, but a few times a campaign you may find it's an excellent defensive tool when you need it. A great addition to a sheet that already has locked in what spells it’s routinely casting with Pact Magic.

14th Level: Hurl Through Hell

Hurl Through Hell is metal. Mechanically, it's a once per long rest that turns a creature you hit with an attack (spell or weapon both work) that basically just adds 10d10 psychic damage to hit by throwing them through six seconds of hell. Them disappearing until the end of your next turn, too, makes this something that can temporarily mitigate a monstrous boss for a single turn, denying them any actions and legendary actions for a full round, opening up a lot of wiggle room to adjust, prep, deal with minions and other monsters, and more. All of that can happen without ever even asking the monster to make a save; all you need to do is hit it once. Hurl Through Hell will make you feel powerful when your pact weapon greatsword chunks them for 3d8+8 damage before bashing them like a baseball through the abyss and back for a bonus 10d10 psychic damage. Once per long rest is a bit infrequent, but for what it does, it merits its infrequent uses. Hurl Through Hell is SWEET.

All Together

While their first level feature is one of the weaker options between all the warlock subclasses, my god is their spell list powerful. Burning Hands, Command, Scorching Ray, Blindness/Deafness,Fireball, Fire Shield, Wall of Fire, and Harrow all can find their way onto an abundance of sheets. On top of that, when built around, Dark One’s Blessing rewards melee, high risk, high reward gameplay with larger quantities of moderate difficulty encounters. Dark One’s Own Luck and Fiendish Resilience are both generic and solid improvements to most characters, shining brighter again on melee fighting style characters. Hurl Through Hell caps the option off with a bang, being a banger of a tool that hits hard and looks cool as hell while doing it. If you want to try out a tankier warlock with the intention of surviving in the front line, or want to blast off a pair of high damage fire spells once per short rest, the Fiend is a great patron for you.

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