Subclass Warlock Great Old One Patron

What Is the Great Old One Patron?

The Great Old One Patron is a debuff-focused Warlock subclass. Mortal Reminder at Level 3 makes every kill a crowd-control event — witnesses must save or become Frightened. Entropic Ward at Level 6 gives you a reaction that burns a Pact slot to impose Disadvantage on an incoming attack. Eldritch Hex at Level 10 lets you choose which ability score to debilitate — imposing Disadvantage on all checks and saving throws for that stat. Thought Shield makes you resistant to psychic damage and reflects it back at attackers.

This is a debilitation-focused Warlock subclass.

Class Features

Progression Overview

LEVEL	FEATURE
3	Great Old One Spells, Mortal Reminder
6	Entropic Ward
10	Thought Shield, Eldritch Hex, Hex (always prepared)

Level 3 Features

Great Old One Spells

Your Patron grants an always-prepared spell list that doesn't count against your Pact Magic limit:

WARLOCK LEVEL	SPELLS ADDED
3	Dissonant Whispers, Hideous Laughter, Detect Thoughts, Phantasmal Force
5	Fear, Hunger of Hadar
7	Confusion, Death Ward
9	Telekinesis

Mortal Reminder

ClarifiedMortality — when you reduce an enemy to 0 HP, creatures within 30 feet that witnessed the kill must succeed on a Wisdom saving throw (DC = your spell save DC) or become Frightened of you until the end of your next turn.

Mortal Reminder turns each kill into a crowd-control event. In fights against groups, landing a kill can cascade — enemies nearby fail their Wisdom saves and spend their next turn unable to approach you, granting your party time and space. The effect scales naturally with your spell save DC.

Level 6 Features

Entropic Ward

EntropicWard — a reaction interrupt with three variants, each costing a Warlock Spell Slot of the corresponding level:

Interrupt_EntropicWard   (base)
Interrupt_EntropicWard_3 — Cost: ReactionActionPoint:1;WarlockSpellSlot:1:3
Interrupt_EntropicWard_4 — Cost: ReactionActionPoint:1;WarlockSpellSlot:1:4
Interrupt_EntropicWard_5 — Cost: ReactionActionPoint:1;WarlockSpellSlot:1:5

• Trigger: A creature makes an attack roll against you
• Cost: Your Reaction + one Warlock Pact Magic slot (Level 3, 4, or 5)
• Effect: The attack is made with Disadvantage
• On Miss: You gain Advantage on your next attack roll against that creature

Entropic Ward is expensive — it costs a Pact Magic slot, which are precious. But the payoff is significant: Disadvantage on an incoming attack, and if it misses, Advantage on your next attack. Against high-accuracy enemies, spending a slot to negate a likely hit is a sound trade.

The three slot levels (3/4/5) let you choose how much investment you make — though the effect is identical regardless of slot level.

The passive EntropicWard unlocks all four interrupts simultaneously:

Boosts: UnlockInterrupt(Interrupt_EntropicWard);
        UnlockInterrupt(Interrupt_EntropicWard_3);
        UnlockInterrupt(Interrupt_EntropicWard_4);
        UnlockInterrupt(Interrupt_EntropicWard_5);
        ActionResource(Interrupt_EntropicWard_Charge,1,0)

Level 10 Features

Thought Shield

Thought_Shield_Psychic_Resistance — a permanent passive with two distinct effects:

Boosts: Resistance(Psychic,Resistant);
        RedirectDamage(1,,Psychic,true)

Effect 1 — Psychic Resistance: You have Resistance to Psychic damage — all psychic damage taken is halved.

Effect 2 — Psychic Reflection: When you take Psychic damage, 1 point of that damage is redirected back to the attacker.

Thought Shield makes the Great Old One Patron Warlock highly resistant to psychic attacks. Psychic damage is halved and 1 point per hit is reflected back to the attacker — meaningful in fights with many psychic hits.

Eldritch Hex

GreatOldOne_10_EldritchHex — the defining Level 10 feature. When you apply Hex to a target, you choose one of six Eldritch Hex variants to inflict alongside it:

VARIANT	STATUS	EFFECT
Eldritch Hex: Strength	ELDRITCH_HEX_STRENGTH	Disadvantage on all Strength checks AND Strength saves
Eldritch Hex: Dexterity	ELDRITCH_HEX_DEXTERITY	Disadvantage on all Dexterity checks AND Dexterity saves
Eldritch Hex: Constitution	ELDRITCH_HEX_CONSTITUTION	Disadvantage on all Constitution checks AND Constitution saves
Eldritch Hex: Intelligence	ELDRITCH_HEX_INTELLIGENCE	Disadvantage on all Intelligence checks AND Intelligence saves
Eldritch Hex: Wisdom	ELDRITCH_HEX_WISDOM	Disadvantage on all Wisdom checks AND Wisdom saves
Eldritch Hex: Charisma	ELDRITCH_HEX_CHARISMA	Disadvantage on all Charisma checks AND Charisma saves

Additionally at Level 10, Hex is added to your always-prepared spell list via a dedicated spell list entry — meaning you never need to use a spell prepared slot on it.

Eldritch Hex is a surgical debilitation tool. Every variant targets both ability checks AND saving throws for that stat — not one or the other, both.

Constitution Hex: the enemy has Disadvantage on Concentration saves. Wisdom Hex: Charm and Fear effects become more reliable. Strength Hex: grapples and shoves become much harder for the target. Choose based on the enemy.

Playstyle Notes

The Great Old One Patron is a psychic debilitator that wins by making enemies less capable rather than by dealing direct damage.

Your combat identity:

1. Mortal Reminder — on every kill, force nearby witnesses to Wisdom save or become Frightened; cascades in multi-enemy fights
2. Entropic Ward — expensive but decisive when a hit would cost too much; Disadvantage on the attack + Advantage on your next
3. Hex — always prepared at Level 10; the foundation of your debilitation kit
4. Eldritch Hex — choose your variant based on the enemy's key stat; Constitution for casters, Strength for melee, Wisdom for smart enemies
5. Thought Shield — passive psychic resistance + reflection; mindflayer encounters become trivially easier