Whore of Babylon

Effects

(Eve) Eve starts with this item by default, and has the following extra effects:
- The item is activated at one full Red Heart or less.
- Her damage multiplier increases from 0.75 to 1.0 when active.
The effect is removed after leaving a room with more than half a heart (more than one full heart for (Eve) Eve).
The effect may not be immediately applied if Isaac has lost red hearts without taking damage; the effect will activate upon entering a new room.
The effect is always active for characters without heart containers, such as (???) ??? and (The Lost) The Lost, though other characters can also lose their heart containers through Devil deals or items like Guppy's Paw or Abaddon.
- (Added in Repentance) This also includes (Tainted Jacob) Tainted Jacob after being hit by Dark Esau.
(III - The Empress) III - The Empress grants a similar effect to Whore of Babylon for the current room which does stack with Whore of Babylon.
- (Removed in Repentance) Stacking The Empress on Whore of Babylon either via multiple cards or multiple activations of Blank Card increases damage by the number of uses squared, e.g. +1.5 * 2 * 2 total damage bonus for using the card on top of activated Whore of Babylon.

(Added in Afterbirth) (Keeper) Keeper: As Keeper cannot have half of a Coin Heart, this item has no effect on him.
(Added in Repentance) (Rotten Heart) Rotten Hearts: Counts as a full Red Heart for the purposes of this item, rendering it impossible to activate (except for (Eve) Eve).
Whore of Babylon: No further effect when multiple copies are acquired.