Tainted Bethany is unable to utilize Red Hearts as health and cannot obtain red heart containers, similar to ???. When picked up, red hearts instead are converted to a resource unique to Tainted Bethany called "blood charges" at the rate of one charge per half heart. The number of blood charges currently owned is listed along with the pickup counters. Blood charges can be consumed to use Tainted Bethany's activated item when the item isn't fully charged, at the rate of one blood charge per empty bar of charge.
Tainted Bethany starts with 3 Soul Hearts, 6 blood charges, and Lemegeton in the consumable slot.
Any items held by Tainted Bethany that give positive modifiers and multipliers have only 75% of their effect. Familiars and Orbitals also deal only 75% of their usual damage. Negative modifiers and multipliers are not reduced.
Lemegeton has a 25% chance to pull from the current room's item pool when creating item wisps, and as such can be abused by Tainted Bethany to obtain large amounts of useful items by saving her blood charges until she enters a room such as Angel Room, Devil Room, Secret Room, Shop, Curse Room, or even a Planetarium.
Blended Hearts will count as red hearts and only contribute towards the red heart charge meter.
Items created by Lemegeton don't count towards Transformations.
Items that normally grant consumables on pickup will not do so if created by Lemegeton.
Good Items[]
2 of Hearts: Doubles the amount of held blood charges.
2 of Hearts + Blank Card: Allows for the creation of infinite blood charges as long as Tainted Bethany has more than 12 blood charges.
Queen of Hearts: Spawns 1-16 full red hearts, granting a potentially very significant number of blood charges.
Queen of Hearts + Any item that can duplicate Queen of Hearts (D1, D Infinity, Rune of Jera + Clear Rune, or Blank Card): Allows for nearly infinite blood charges.
Car Battery: Causes Lemegeton to be used twice upon activation, spawning two passive wisps on use.
Charm of the Vampire: Gives blood charges every 15 enemies killed, allowing exploitation of some enemies to farm infinite blood charges.
Converter: Grants blood charges upon use with no change to health, allowing to get a blood charge every two rooms, and two charges every three rooms.
Eraser: Eraser can be charged and used with blood charges, allowing multiple uses per floor.
Leech: Gives 1 blood charge per enemy killed. Can farm infinite blood charges with enough patience and Door Stop / Mercurius.
Little C.H.A.D.: Essentially grants one blood charge every three rooms.
Maggy's Bow: Doubles blood charges gained when picking up red hearts.
Mega Battery: Both Tainted Bethany's held active item and Lemegeton are overcharged.
Red Key: With her blood charges, Tainted Bethany can explore more red rooms than other characters, allowing her to gain the benefits of red special rooms easily. In turn, this allows her to use Lemegeton to gain items from those item pools in addition to their normal contents.
Satanic Bible: This item is particularly well-suited for Tainted Bethany, as blood charges may be used to repeatedly activate Satanic Bible and potentially compensate for the price of the Devil Deal that spawns in place of the boss room item pedestal.
Activating Lemegeton in a boss room after activating the Satanic Bible on that floor will cause it to pull from the Devil Room item pool when creating wisps. This works even on bosses that don't normally drop a standard boss room item, such as Mom, Satan, or ???.
4.5 Volt: Charges gained from 4.5 Volt will charge any active items in the active item slot first. If said active item is fully charged, charge will instead be added to Lemegeton.
Jumper Cables: Same effect; active item will be charged first.
Lil' Battery: Same effect; active item will be charged first. If more charges than necessary for full charge are added, remaining charges will be lost, and not be added to Lemegeton. If picked up when active item is fully charged, charges will be added to Lemegeton.
The Jar: Hearts will only collect in The Jar after achieving 99 blood charges.
Red heart restoration: All items and effects that restore red hearts directly will instead add blood charges.
Full heal effects, however, do not give anything.
Trivia[]
When Tainted Bethany dies, the orb embedded in her forehead stops glowing.
The achievement for unlocking Tainted Bethany is "The Zealot", a possible title for the character.
A zealot is someone with fanatical devotion to their faith or ideals.
Tainted Bethany's design is based off of the Exorcist and Necromancer enemies from The Binding of Isaac:Antibirth.
Tainted Bethany's locked character icon, depicting a closet door with a inverted cross and bloodstains on it.
Bugs[]
Bug!
Obtaining Polydactyly as Tainted Bethany will still allow you to hold two consumables alongside the book. However, if it is acquired through Lemegeton wisps, it could end with her losing the book completely if the wisp is dissipated, as picking up a consumable after losing Polydactyly could get rid of Lemegeton entirely.
Bug!
Certain items that spawn blue flies in large quantities can cause wisps to disappear (further testing required).
Bug!
Notched Axe can be used once fully depleted of regular charges, as long as Tainted Bethany has at least one blood charge remaining. Notched axe does not deplete blood charges, and needs to be reactivated every time it is used to break a rock or open a secret room.
Bug!
Using Glowing Hour Glass and Sharp Plug while having at least 2 full hearts allows you to repeatedly use Glowing Hourglass and duplicate Lemegeton wisps allowing you to have infinite copies of said wisps.
Bug!
Using Sacrificial Altar with item wisps will remove them without immediately removing the effects. The effects will be removed upon the next use of Lemegeton.
Bethany. Tainted Bethany is unlocked by reaching 
Home and using the 
Red Key, 
Cracked Key, or 
Soul of Cain to access a special room in one of the walls while playing as Bethany.
Red Hearts as health and cannot obtain red heart containers, similar to 
???. When picked up, red hearts instead are converted to a resource unique to Tainted Bethany called "blood charges" at the rate of one charge per half heart. The number of blood charges currently owned is listed along with the pickup counters. Blood charges can be consumed to use Tainted Bethany's activated item when the item isn't fully charged, at the rate of one blood charge per empty bar of charge.
Soul Hearts, 6 blood charges, and 
Lemegeton in the consumable slot.
Angel Room, 
Bug!
Polydactyly as Tainted Bethany will still allow you to hold two consumables alongside the book. However, if it is acquired through Lemegeton wisps, it could end with her losing the book completely if the wisp is dissipated, as picking up a consumable after losing Polydactyly could get rid of Lemegeton entirely.
Notched Axe can be used once fully depleted of regular charges, as long as Tainted Bethany has at least one blood charge remaining. Notched axe does not deplete blood charges, and needs to be reactivated every time it is used to break a rock or open a secret room.
Glowing Hour Glass and 
Sharp Plug while having at least 2 full hearts allows you to repeatedly use Glowing Hourglass and duplicate 
Sacrificial Altar with item wisps will remove them without immediately removing the effects. The effects will be removed upon the next use of 
Bethany Unlocks 
Tainted Bethany Unlocks 
Characters 
The Binding of Isaac: Rebirth 
Achievements
Attributes
Bosses
Cards and Runes
Challenges
Chapters
Characters
Co-op
Items
Item pools
Monsters
Objects
Pickups
Pills
Rooms
Seeds
Transformations
Trinkets
