Eve

“	And Adam called his wife's name Eve; because she was the mother of all living.	”
–Genesis 3:20

Eve is the sixth unlockable character added in the Halloween Update. She is unlocked by making two or more deals with the devil in one playthrough.

When she is in the Whore of Babylon form, her attack is multiplied (x3) and a screen will appear saying, "What a horrible night to have a curse..." (a reference to Castlevania II: Simon's Quest). She starts with no coins, bombs or keys.

Strategy

Eve starts with a small health pool and great speed, only matched by Cain. She has the lowest base damage but this can be increased by taking damage, which activates the Whore of Babylon effect upon reaching 1 Red Heart. Eve is rather lackluster without the offensive boosts provided by her unique starting item, so the Whore of Babylon is what allows players to fight more effectively.

What you're going to want is to have your main starting item, Whore of Babylon, become a permanent bonus, which can be done by bringing your Heart Containers down to only half a heart remaining, then amassing Soul Hearts (Book of Revelations comes in handy, Guppy's Paw is even better if you can obtain it). Then spend regular hearts on Blood Donation Machine or deals with the devil until you get to a cursed mode, greatly increasing damage.

Another solution (Wrath of the Lamb only) is to use Guppy's Paw for all of your hearts, giving you technically zero Heart Containers, but giving you a permanent Whore of Babylon and a good lot of Soul Hearts. Consider Dead Bird as a bonus, don't get hurt specifically for it to spawn as Eve (like Cain or Judas) is a very fragile character initially, and you must do your best to conserve health in order to survive. In Wrath of The Lamb, The Polaroid is useful, as well as necessary to access The Chest, as it grants a shield for 5 seconds when the player is reduced to half a heart. This means that when in the Whore of Babylon state, the player will also be invincible for 5 seconds at a time after taking damage no matter what (especially useful if using Guppy's Paw).

Items

Best Items

Items that take Heart Containers away from Eve are ironically good items as they can help her to get into the Whore of Babylon mode. Items that grants Soul Hearts are also useful as they can keep Eve vital without getting out of Whore of Babylon mode.

Items

Guppy's Paw
IV Bag
Blood Rights
Razor Blade
The Nail
The Pact
Book of Revelations
Mitre
The Relic
Rosary
1UP
Dead Cat
Ankh (permanent Whore of Babylon state after death)

Trinkets

The Polaroid (Although necessary with every character to access The Chest, it is especially useful combined with Whore of Babylon when on using Soul Hearts)
Mom's Pearl (Increases the chance of Soul Hearts spawning instead of normal hearts, pairs well with the Mitre)

Good Items

Items that trigger on damage are good on Eve as well. However, since they usually take away Soul Hearts first, they are generally less useful.

Items

Trinkets

Bad Items

Items that heal Red Hearts for Eve are bad for her, if the player is aiming for a Whore of Babylon-focused play-style.

Items

Blood Bag
<3
Yum Heart
Little C.H.A.D.
Charm of the Vampire
Magneto (Can drag hearts to Eve, making her accidentally pick them up)

Trinkets

Related Achievements

Eve's Dead Bird - Make two deals with the devil in one playthrough.
The Razor Blade - Kill Mom's Heart with Eve.
The Demon Baby - Complete Sheol with Eve.
The Sacrificial Dagger - Complete the Cathedral with Eve.
Eve's Bird Foot - Complete The Chest with Eve.
Eternal Eve - Complete The Chest with Eve on Hard Mode.

Trivia

Much like Magdalene, Eve is just Isaac in a wig, with a bit of eye shadow, similar to the eye shadow that the Ankh gives him.
Eve is shown in her curse state when she is locked, but when she is unlocked she appears normal.
A full playthrough does not have to be done to unlock the character, as making two deals with the devil will instantly unlock her.
Edmund has stated that Eve is his favorite character due to her unique risky play-style.
Edmund confirmed on his Formspring that Eve is the "Druid" class.^[1]
Eve gets her name from the biblical Eve, who was the first woman and first sinner.
Unlocking Eve is likely a reference to the Bible when the Serpent tricks Eve into eating from the Tree of Knowledge, the first sin.
The Whore of Babylon ability is most likely a reference to the Book of Revelation, where the angels bring John to witness the judging of the great whore, Babylon.
When down to 1/2 of a heart, Eve leaves a pool of blood instead of the usual urine from the other characters (This is not due to the Whore of Babylon, as other characters can obtain the curse and still leave urine). This is most likely in reference to God's punishment for Eve's original sin. In the Bible, God punished Eve by making childbirth painful and making women menstruate. The pool of blood is likely menstrual blood.
- This has been debunked by Florian, the pool of blood is indeed due to her demon transformation.
Eve has a 16.25% chance instead of the usual 10% for any nonspecific Heart drop to turn into a Soul Heart.
If the player was to buy/find Brimstone, The Pact, Lord of the Pit, or anything else that turns Isaac demonic, the game will think that Eve is in game instead of Isaac and therefore will not unlock her.