A common Tarot card that hands you a Black Heart, turning the moment you take damage into a screen-wide blast against every enemy.
The Diseased Heart is the rare defensive card that punishes the enemy for hurting you. The instant you lose one of its hearts, every enemy on screen takes damage, so getting hit becomes a counterattack instead of a setback.
It is a common Tarot card. According to the wiki, the Diseased Heart is a default-unlock card with an effect that simply reads gain one Diseased Heart, also known as a Black Heart.
The value is in the heart it grants. The wiki specifies that Diseased Hearts sit ahead of your Blue and Red health in the damage order, so they act as a retaliating buffer before your real health is touched.
This guide covers what the Diseased Heart card does, how Black Hearts work, the Frozen and Molten variants in the same family, and the builds that make it shine.
A default Tarot card, granting one Diseased Heart.
Losing the heart damages all enemies on screen.
Aggressive, high-contact builds that expect to take hits.
You play a no-hit style, since it never triggers.The Diseased Heart is a Tarot card that grants a single Black Heart when drawn. Per the wiki, it is a default-unlock 
Tarot card with a common draw weight, so it shows up often during a crusade.
Its worth is entirely in the heart it hands you. The card itself is captioned "a heart rife with vicious corruption," and the wiki notes it also damages enemies on screen when you are hit, which is the Black Heart mechanic in action.
Because it is common and defensive, it stacks well over a run. Drawing several Diseased Heart cards builds a wall of retaliating hearts, which pairs naturally with the curses and weapons that want you fighting up close.
Diseased Hearts, also called Black Hearts, are a special health type with a built-in counterattack. Per the wiki, losing one deals damage to every enemy currently on screen, so each hit you take fights back for you.
They behave like Blue Hearts otherwise. According to the wiki, Diseased Hearts are lost when a crusade ends and cannot be restored by standard 
healing, and they do not come inside a Heart Container the way Red Hearts do.
They also sit early in the damage order. The wiki specifies that incoming damage removes Molten and Frozen Hearts first, then Diseased Hearts, then Blue Hearts, then Spirit, and finally Red, so a Black Heart soaks a hit before your real health while nuking the room.
In practice the Diseased Heart shines in packed rooms. The more enemies on screen when a Black Heart pops, the more total damage the retaliation deals, so it is strongest exactly when you are most surrounded.
The Diseased Heart is one of three retaliating heart types, each tied to a different status effect. The table below shows the family the wiki groups it with.
| Heart | Effect When Lost |
|---|---|
| Diseased Heart | Damages all enemies on screen when lost. |
 Frozen Heart | Freezes all enemies on screen when lost. |
 Molten Heart | Burns all enemies on screen when lost. |
The elemental two come from Woolhaven bosses. Per the wiki, Frozen Hearts and Molten Hearts are tied to 
Scylla and her brother Charybdis at the Molten and Frozen Hearts pools, while the Diseased Heart is the base-game version you can draw as a Tarot card from the start.
Build around taking controlled hits. The Diseased Heart rewards an aggressive, high-contact style, so it fits melee weapons that put you in the middle of a fight rather than a cautious ranged approach.
Pair it with damage multipliers. Because the retaliation scales with your overall damage, stacking it under the 
Golden Fleece or a strong 
legendary weapon setup turns each hit you absorb into a heavier blast.
It also covers a weakness of glass builds. The Glass Cannon Fleece trades health for damage, and the Diseased Heart gives that fragile build a way to turn the hits it will inevitably take into extra clearing power.
Stack multiple Diseased Heart draws when you can. Across a long crusade the hearts add up, and a row of Black Hearts lets you tank several hits in a boss rush while each lost heart chips the boss and clears its adds.
The Diseased Heart is one card in a deep crusade toolkit. These guides cover the cards, weapons, and resources that make a run stronger.
Game data and screenshots adapted from cult-of-the-lamb.fandom.com, used under CC BY-SA 3.0. Original content remains the property of the wiki contributors and Massive Monster and Devolver Digital.