Heart-Eater (5A)

This is a Warlock otherworldly patron for 5A.

Source: James J. Haeck in En5ider 194.

Streaks of red bleed into your vision, and you feel your life end. You open your eyes and gaze out upon a claustrophobic, lightless chamber. A searing pain flashes through your chest, and you feel an incredible weight within it, pulling you down and pinning you to the ground. From the darkness emerges two crimson lights—eyes, fixated upon your prostrate form. A voice bubbles out of the darkness, addressing you. “Your heart is killing you. Moments from now, back in the world of the living, your heart will pump the last drops of precious blood out of the wound in your body.” A hand emerges from the void, concealed within a white glove stained with blood. “I can save your fragile life and return you more powerful than before. All I ask for in return is your treacherous heart.”

The legend of the Heart-Eater is a story told by veterans of war—some old and scarred, others young and freshly wounded. It is told by folk who’ve dined at death’s door and somehow returned to tell the tale. In their stories, the Heart-Eater appears as a monster in the dark, stinking of iron and smiling hungrily like the skull of Death itself. The Heart-Eater’s appearance varies. There was a young commoner who was stabbed in the chest by a mugger, and was awoken by gentle kiss and a delicate hand on his chest. There was a middleaged sage whose experimental spell wreathed her in flame, but was saved by a woman made of starlight who passed through the flames unburned. In all these stories, only one thing is constant. The Heart-Eater appears before you when you are on the verge of death and offers to save your life— and only asks for your heart in return.

Meeting the Heart-Eater

The Heart-Eater is a new warlock patron that is best used as a tool for the Game Master. While it can be offered to players as a character customization option, it is most potently deployed when a warlock rolls their third death save—and dies. The Heart- Eater appears to the dying warlock in the split second before they die, supernaturally stretching that instant into minutes. In those precious minutes, it offers them a second chance at life. It whispers that their heart has betrayed them, stupidly pumping their lifeblood into the dirt through a mortal wound, and offers to save their life by taking their treacherous heart from their chest and replacing their blood with magic.

A character that accepts the Heart-Eater’s offer is restored to full hit points and the Heart-Eater demands that they break their pact with their current patron and take it as their new patron instead. In addition to implying that there will be strong (but interesting) narrative consequences to this decision, the GM should make it clear to the player that this choice will have a mechanical impact on their character.

The roleplaying implications of breaking a pact are left to you to decide, but some samples are provided below. All these effects last no more than 1d10 days, but there might be recurrences at a later time.

Pactbreaker Table: The Archfey (1d4)

The Archfey infests the pactbreaker’s camp with a poltergeist (variant specter that is a fey).
Whenever the pactbreaker casts a spell of 1st level or higher, they must make a DC 10 Wisdom saving throw. On a failure, they are transported to a dangerous location in the Feywild for one minute. This event happens only once.
When the pactbreaker wakes up from their next long rest, they find the Archfey in bed with them, in humanoid form and wearing a regal ensemble. The Archfey is not angry, but wants to know what went wrong in their relationship.
When the pactbreaker wakes up from their next long rest, a massive bouquet of otherworldly lilies has been left next to their bedroll. On it is a card written in elegant, flowing script that reads: “Sorry to see you go. Safe travels—I hope we never meet again, or else.”

Pactbreaker Table: The Fiend (1d4)

The Fiend hires a company of fiendish mercenaries from Gehenna to pursue the pactbreaker and deliver their soul to him. This company is comprised of 1d6 fiends of the GM’s choice. They locate the pactbreaker within 1d10 days unless prevented by magic such as the Nondetection spell.
The Fiend manipulates flames around the pactbreaker, causing the pactbreaker to gain vulnerability to fire damage for the next 1d10 days.
The Fiend tries to subvert the Heart-Eater’s power. Whenever the pactbreaker casts eldritch blast, it deals fire damage instead of force damage. This is a curse and can be removed by Remove Curse and similar means.
For the next 1d10 days, all food the pactbreaker eats tastes of ashes and all liquids the pactbreaker drinks tastes of oil. They must succeed on a DC 10 Constitution saving throw or vomit after completing a meal. This is a curse, as above.

Pactbreaker Table: The Old One (1d4)

When the pactbreaker next takes a long rest, they must make a DC 13 Wisdom saving throw. On a failure, the pactbreaker is plagued by horrifying nightmares of the Old One’s revenge and only gains the benefits of a short rest instead. These dreams only happen once.
Whenever the pactbreaker rolls initiative, they must make a DC 13 Wisdom saving throw as the Old One summons shadowy visions of every creature the pactbreaker has ever killed. On a failure, the pactbreaker’s speed is reduced to 0 until the end of their first turn in combat.
The pactbreaker must make a DC 10 Wisdom saving throw when they make their first attack in a combat encounter. On a failure, the Old One takes over their mind and attacks the nearest friendly creature instead of the attack’s target, then relinquishes control of the pactbreaker’s mind. This effect only happens once.
For the next day, the pactbreaker’s arms are replaced by tentacles after they complete a long rest. The pactbreaker’s arms return to normal after completing another long rest.

Otherworldly Patron: The Heart-Eater

The Heart-Eater hungers for the emotions of life. It longs to feel love and hatred, anxiety and elation. By making a pact with you and taking your heart, the Heart-Eater leaves your chest light and free. It constantly urges you to live life to the fullest and experience all the dizzying highs and despairing lows that reckless life brings. Yet you never feel fully satisfied, for little do you know that your patron steals your emotions from your empty chest, feeding upon their potency. Though you look the same and may seem the same to casual acquaintances after making a pact with the Heart-Eater, close friends may realize that something has changed in you. You are brighter, more energetic, and less risk-averse in public, but grow dour, depressed, and even cruel in private.

You may try to regain your heart in order to break your pact with the Heart-Eater, doing so could be the goal of an adventure or an entire campaign.

Expanded Spell

List The Heart-Seeker lets you choose from an expanded list of spells when you learn a warlock spell. The following spells are added to the warlock spell list for you.

Heart-Eater Patron Spells

1st False Life, Sleep

2nd Alter Self, Calm Emotions

3rd Bestow Curse, Nondetection

4th Death Ward, Polymorph

5th Bigby's Hand, Modify Memory

Heartless

Starting at 1st level, your patron plucks your heart from your chest, dulling your emotions. You have advantage on saving throws against being charmed or frightened. Additionally, any effect that changes your emotional state, such as being charmed, frightened, or entering a barbarian Rage, affects you for only half its usual duration. An effect that lasts one round or less expires at the beginning of your turn.

Bloodless

Also at 1st level, you no longer bleed, for your life is sustained by the magic of your patron. You are immune to spells and effects that require a target to have blood. When you are reduced to 0 hit points, you do not make death saving throws. You can still fail death saving throws when you take damage while at 0 hit points.

Arcane Vitality

Starting at 6th level, the magic that courses through your veins fortifies you whenever you call upon the Heart-Eater’s strength. When you cast a warlock spell of 1st level or higher, you gain temporary hit points equal to twice the level of the spell slot used.

Cruel Retribution

Starting at 10th level, you are quick to retort to any slight. When you are hit by an attack, you can use your reaction to make a melee weapon attack or cast Eldritch Blast at the creature that attacked you. If your attack hits, you can choose to reduce the target’s speed to 0 until the start of its next turn. Once you do this, you cannot do it again until you complete a short or long rest.

Heartseeker

Starting at 14th level, when you hit a creature with an attack, you can use this feature to cause the attack to strike its heart directly. The attack’s damage is tripled and the creature must make a Constitution saving throw against your warlock spell save DC. On a failed save, it is paralyzed for 1 minute. It can repeat this saving throw at the end of each of its turns, ending the effect on a success. If this damage reduces the creature to 0 hit points, the creature dies and its heart appears in your hand. Once you use this feature, you can’t use it again until you finish a long rest.

Eldritch Invocations

Bloodless Blade

Prerequisite: Heart-Eater patron, Pact of the Blade feature. When you hit with an attack using your pact weapon, you can spend a number of temporary hit points up to your warlock level. The target takes extra force damage equal to the number of temporary hit points you spent.

Devour Emotions

Prerequisite: Heart-Eater patron, Pact of the Tome feature You can cast Calm Emotions once without using a warlock spell slot. You can’t do so again until you finish a long rest. Additionally, whenever you cast Calm Emotions, you gain temporary hit points equal to twice the number of creatures that fail their saving throw. These temporary hit points stack with temporary hit points gained from the Arcane Vitality feature for casting Calm Emotions.

Heart Familiar

Prerequisite: Heart-Eater patron, Pact of the Chain feature The Heart-Eater grants you a familiar sustained by your own heart. This familiar can be any elemental of challenge rating 1 or lower, and can be summoned using the find familiar spell. As long as you and your heart familiar are on the same plane of existence, you can choose to have the familiar takes only half damage from all sources, but the other half is transferred to you. Additionally, your heart familiar’s attacks count as your own attacks whenever you use a warlock class feature that requires or allows you to make an attack roll.

Editor's Notes

I like all the theme work here, but I suppose this was made to introduce an important plot line in a long campaign. There is an implied promise of such a subplot, but it may not happen in every game with a heart-eater warlock.