However, if the Razor Blade has not been unlocked by defeating Satan with Eve, Eve will not start with the Razor Blade until both conditions have been fulfilled.
Unlike other characters, Eve's Whore of Babylon's effect activates with one remaining red heart, instead of half a heart, and it will set her damage multiplier to 1.00.
When unlocking Eve, gaining heart containers does not count as picking up heart pickups.
Guppy's Paw is also a useful item for building up damage, providing soul hearts and free Whore of Babylon during the run.
Curse Rooms are usually pleasant to find at the beginning of a run, since without health upgrades, they will lower Eve's health into her Whore of Babylon state, and can potentially hold useful items and/or Soul/Black hearts to protect Eve after transforming. If not already active, be sure to damage yourself upon the curse room door before accepting Soul or Black hearts to activate the Whore of Babylon state.
Good items:
Items that take red heart containers away typically do so as a cost to counterbalance its potent benefits; for Eve however, this supposed cost will likely be beneficial due to Whore of Babylon. Such items include Dead Cat, Guppy's Paw, and Abaddon.
Following the same logic, items that make deals with the devil more likely will allow Eve to trade her red heart containers away more reliably, making it safer to gain health for the sole purpose of spending it in a Devil Room.
As Eve will prefer having little to no red hearts, she will need alternative ways to stay alive. As such, items that are conducive of spawning soul hearts or black hearts will be instrumental for Eve. Such items include Dark Bum, Book of Revelations, Satanic Bible, Mitre, and many more.
The Polaroid works very well with the Razor Blade, when Eve is at half-a-red-heart or less. During the period of invincibility after taking damage, the player can spam the Razor Blade quite a few times and vastly increase Eve's damage with no penalty.
Items that activate with low health such as Dark Prince's Crown work well with Eve.
Bad items:
Any items that give Eve red heart containers are potentially bad since it could deactivate the Whore of Babylon effect. However, because heart containers are very useful in deals with the devil, it could also benefit Eve greatly to hold on to the containers temporarily. Thus, an understanding of Devil Room spawning occurrence and chance is essential in deciding whether or not to take such items.
Items that heal red heart containers (such as Placenta, Charm of the Vampire, and the Error: The given collectible ("Tick") does not exist.) can, and oftentimes, inevitably will cancel the effect of Whore of Babylon, if Eve has more than one red heart container.
Items that attract pick-ups will force Eve into avoiding red hearts so she could keep the Whore of Babylon effect, should she have more than one red heart container.
Error: The given collectible ("Child's Heart") does not exist. causes more red hearts to appear, something which is generally undesirable in an Eve run without Dark Bum, and can make more useful items such as bombs or keys less likely to appear.
Eve was a playable character in the original Binding of Isaac.
In the original, Eve was unlocked by making two or more devil deals in one run. This unlock method was given to Azazel in Rebirth.
According to biblical theology, Eve was the first woman on earth, born of Adam's rib in the book of Genesis.
In the original game, Eve had a unique effect in that she would leave a bloodstain when entering a room at half a heart remaining instead of a urine stain. This was thought to be a reference to menstruation, as biblically menstruation was a curse upon Eve given by God. It is unknown if this feature was intentionally left out or was simply overlooked in Rebirth. This feature was re-added in Booster Pack #5.
Whore of Babylon, and the 
Dead Bird.
Eve will also start with the 
Eve will also start with the 
Characters 
The Binding of Isaac: Rebirth
