The Great Old One 5E | Warlock Subclass Guide

great old one warlock

The Warlock class… A master of the connection between man and myths! In the Player’s Handbook, one of these connections is between mere mortals… And things that should never be seen, heard, or experienced. That’s right; in today’s guide, we are going to see what happens to Warlocks who form pacts with beings beyond the veil of reality. From Ghaunadar to Cthulhu, these Warlocks are always strange and quirky… But, above all, they know far more than anyone should. Get the scoop with our Great Old One Warlock Guide

See the Future: The Great Old One Warlock 5E Guide

The Great Old One, despite being a Warlock Patron with enchanting flavor, can’t exactly dominate your mind like these entities normally would. No, no… Instead they grant you information, defenses, and utility. When it comes to both crowd control and discovering new knowledge, the Great Old One is one of Warlock’s finest tools. And when it comes to defending yourself from attack… You can do a bit better.

Expanded Spell List

As mentioned above, this patron focuses primarily on information, with some slight crowd control as a bonus. The spells reflect this focus, with a few outstanding entries, but mostly niche abilities.

GOOlock Expanded Spells
  • 1st Level – Dissonant Whispers, Tasha’s Hideous Laughter
  • 3rd Level – Detect Thoughts, Phantasmal Force
  • 5th Level – Clairvoyance, Sending
  • 7th Level – Dominate Beast, Evard’s Black Tentacles
  • 9th Level – Dominate Person, Telekinesis

Dissonant Whispers and Tasha’s Hideous Laughter are both rather potent spells. Whispers causes a creature to move as far away from you as they possibly can… Which normally doesn’t outrange Eldritch Blast. Perfect for keeping your d8 self safe from harm! Meanwhile, Tasha’s Hideous Laughter is an extremely powerful spell; a slightly worse Hold Person. Since you don’t get Hold Person… Not a bad idea.

Detect Thoughts is, as usual, rather powerful in the right situations, so take it if you want information from tight-lipped humanoids. It does have some use for finding invisible creatures, but this is probably not the best way to do so. Phantasmal Force is actually a pretty fantastic illusion spell, letting you deal okay damage and have good utility. In terms of an illusion spell for Warlocks… You could do worse.

Clairvoyance is one of the strongest information spells in the game, boasting fantastic range, good sensory allowance for the caster, and really good safety. The problem is that it’s a preparation spell, requiring 10 minutes to cast. Very much worth your while, if you’re the information tool of the group. Sending is slightly less useful. Take this only if your GM is sending you farther and farther away from an important NPC.

Evard’s is decent area control, if you’re in dire need of that. Dominate Beasts is super situational, and usually not worth the spot in your spells known list. Dominate Person is much better, since humanoids tend to become stronger than beasts. Telekinesis is a good party trick, and the amount of utility options you’ll get is rather fantastic.

Overall, a really unique mix of information and crowd control. You’ll find a lot of use out of this spell list, and it offers good options at almost every level.

Awakened Mind

Time to get woke!

Starting at 1st level, your alien knowledge gives you the ability to touch the minds of other creatures. You can communicate telepathically with any creature you can see within 30 feet of you. You don’t need to share a language with the creature for it to understand your telepathic utterances, but the creature must be able to understand at least one language.

There are countless uses for communicating with a creature telepathically, especially when they wouldn’t ordinarily understand your language. According to a 2015 Sage Advice update, Awakened Mind only allows one-way communication. Although as Jeremy Crawford has said, allowing this ability to work two ways can make for fun homebrew if your DM allows it.

Entropic Ward

And now, for a once per rest defensive ability.

At 6th level, you learn to magically ward yourself against attack and to turn an enemy’s failed strike into good luck for yourself. When a creature makes an attack roll against you, you can use your reaction to impose disadvantage on that roll. If the attack misses you, your next attack roll against the creature has advantage if you make it before the end of your next turn.

Noticeably, this is a pretty wide-reaching ability. Spellcasters use attack rolls to deliver cantrips and ray spells, meaning you can get some value off of this, no matter the target. Unfortunately, it only lets you target yourself. You can’t use this to save a Wizard about to get launched into next week by an Owlbear… But you can keep yourself from the same fate!

The good part of this ability is that you get advantage on the attack roll if the disadvantage works out. A lot of Warlock’s best tools use attack rolls – Vampiric Touch, Eldritch Blast, your Pact Weapon – so gaining advantage on those is worth quite a bit.

Warlocks also love short rests, so this ability will refresh itself constantly. You might not want to short rest just to refresh this, but your spell slots will thank you.

Thought Shield

This class gets a lot of defensive abilities, and this one is no different!

Starting at 10th level, your thoughts can’t be read by telepathy or other means unless you allow it. You also have resistance to psychic damage, and whenever a creature deals psychic damage to you, that creature takes the same amount of damage that you do.

This ability is essentially 3 separate ones, all of them defensive!

The immunity to mind-reading is perhaps the most situational abilities in the entire game. There will be times when you have to “roll a Wisdom Save” or have the BBEG know everything you’ve ever known, but… At that point, Nondetection might serve you better. This doesn’t keep you from Clairvoyance or Locate Creature; just spells like Detect Thoughts. Not exactly horrendous, but not worthwhile either.

So you want that psychic resistance, an ability Barbarians occasionally dream about (when they aren’t dreaming of wanton destruction). Psychic damage is one of the hardest damage types in the game to resist, and it’s only 1/3rd of your level 10 pact ability. That’s pretty fantastic! Psychic damage is, unfortunately, also one of the rarest types of damage. Against beings like Mind Flayers and psychic casters, you’ll get a lot of mileage out of this. But, by itself, it’d be pretty insignificant.

The damage reflection aspect is a good but non-synergetic bonus to the resistance. What, you take half the damage from these psychic spells, and then you reflect it back? That doesn’t seem super useful. Well… That’s because it really isn’t. At least you deal some damage when you eventually do take psychic damage. And most casters like to have a Concentration spell active, so… At least there’s another chance for them to fail?

Create Thrall

The final boon given to you by your dark lord is a legitimate reason to take the subclass by itself.

At 14th level, you gain the ability to infect a humanoid’s mind with the alien magic of your patron. You can use your action to touch an incapacitated humanoid. That creature is then charmed by you until a Remove Curse spell is cast on it, the charmed condition is removed from it, or you use this feature again. You can communicate telepathically with the charmed creature as long as the two of you are on the same plane of existence

At-Will Charm Person with no save. That’s pretty significant.

There’s two huge things weighing this down; incapacitated and touch. Incapacitated means that the target can’t really do anything at all. That requires you to have spent some amount of time or resources on the target. Thankfully, spells like Tasha’s Hideous Laughter incapacitate a target, giving you a pretty easy way to get this ability off… Given they fail two saves. There are other slightly better ways to get it, and if you have any group synergy, your opponent won’t have much time before they’re charmed. The touch aspect isn’t hugely problematic, as long as you’re within one move action from the frontlines.

So, then we have to talk about Charm as a condition. What is Charm worth? It depends on your GM, but this charm effect is stronger than most; it doesn’t end if you hurt the creature, nor if you harm the creature’s allies. That means this Charm is removable just by a handful of spells or if you use this feature again. 

This is a really, really good way to keep a bad enemy permanently out of your hair. If you spend your actions to tell them to fight for you, you can get really big mileage out of this new best friend. Force a Barbarian Chieftain to fight demons for you, force a politician to become your puppet… The possibilities are endless!

It does require setup, and it takes actions to get the biggest benefits from it. But, Create Thrall is useful in any campaign; combat or otherwise.

Pact Boon Synergies

The Warlock gets to choose one out of three pact boons at level 3. The Great Old One actually benefits from all of them, though none have quite the obvious synergies as other Patrons.

Pact of the Blade

Thanks to the durability of Entropic Ward and Thought Shield, the Pact of the Blade gets a surprising amount of synergy with this Patron. While you don’t gain any intrinsic bonuses to damage with your Patron, you do have several strong short-ranged abilities – such as Create Thrall – that are better the closer you are to combat. Combine that with Entropic Ward’s bonus to attack rolls, and you have a legitimate reason to be in melee. This is the weakest pact for the Great Old One, but certainly not unusable.

Pact of the Chain

My personal favorite for this subclass. Familiars offer a rather substantial amount of information for your party, able to easily scout rooms while hiding in corners. Considering the rather tricky options given to the Pact of the Chain, your options expand quite greatly for espionage. You can use your Entropic Shield to give advantage to your touch spells through your familiar, increasing your range to 100 ft. You also can use your telepathy to act like your Familiar is talking to people; You’ll be the best ventriloquist around!

Jokes aside, this is probably the best choice, if you don’t have rogues or anything like that. Imps are the strongest familiar choice, but all of them have unique ways to scout and be useful in combat.

Pact of the Talisman

The Great Old One makes for an okay support character, usually through using debuffs. The Pact of the Talisman can let the Great Old One become an okay defensive caster through adding d4 to saving throws to a frontliner who needs it. But, most of the utility from Pact of the Talisman can be replicated through Pact of the Tome. We’re not desperate for the Talisman, though it can be nice to have around if your frontliners need help.

Pact of the Tome

Bonus cantrips are useful for this subclass, unsurprisingly. With options from the Wizard and Cleric spell list, you can get legitimately powerful cantrip options for either utility or covering different damage options. If you’re wondering what cantrips are most useful, I’d check out our Wizard cantrip and Cleric cantrip guides.

Besides, I feel like Cthulhu would love to give people the “Book of Shadows” whenever it can!

Best Race for The Great Old One Warlocks

While any race can excel as a Warlock, these ones really, really like Charisma. Depending on your build path, you’ll either want to focus on Dexterity or Charisma, and then Constitution. Your Charisma matters because you want the best DCs possible for Hideous Laughter and other powerful spells.


Perhaps the obvious choice. Half Elves help the Warlock out a lot. The charisma bonus is huge, and you get two versatile +1’s to apply to Constitution and either Strength or Dexterity. Darkvision is a great ability, and Skill Versatility is gigantic for the Great Old One’s role as an informant.

If you don’t want to be the generic Half Elf, then the Drow from the Sword Coast Adventurer’s Guide gives you extra utility with racial spell slots. That’s really good for a Warlock!


If you want a good option for Pact of the Blade, Dragonborn is quite viable. The bonus Charisma is, of course, fantastic. The massive boost to Strength gives you a reason to pick up Pact of the Blade for a reason other than Finesse weapons. You may want to use one of your Ability Boosts to pick up Medium Armor proficiency (or consider Multiclassing to get it!), but it’s not a bad option for you.


And, for your Volo’s pick, the Aasimar is a wonderful choice! Charisma is, as usual, a great choice for you. You’ll also get some much-needed damage resistances to help your d8 hit dice. Choose the Fallen option if you want Strength weapons, the Scourge if you’d rather get some health. Either way, you’ve got a great option for a Great Old One Warlock… Even if it’s thematically strange.

Conclusion – Our Take on the Great Old One Warlock Patron

The Great Old One is a mix of utility, defense, and crowd control. It has next to no aggressive abilities, and thus suffers as a frontliner. You’re relying only on the aggressive abilities of the base Warlock, and frankly?

That’s plenty good enough. This pact synergizes super well with the Eldritch Blast invocations, and can give the Warlock some very useful abilities outside of the normal blasting that the class is known for. Try it out if you’re missing a Wizard or other information option. That wraps up our Great Old One Warlock Guide. Need more warlock in your life? Check out our comprehensive Warlock 5E Guide!

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