Benighted Cain and Abel is an unlockable character in Benighted Soul, a mod for The Binding of Isaac.

Cain:
Portable Farm (Consumable slot)
Falsehood of Abel (Finishing Graze! required)

Abel:
Goatify (Consumable slot)
Falsehood of Cain (Finishing Graze! required)

Touch together to switch Main / Second character (with short invincibility).

No switch over 28 seconds hurts Second for 1.5 hearts damage.
(No penalty)

Holding the map key stops Main;
Holding the drop key stops Second.

Second has spectral tears, ignores most damage and goes through obstacles, while move and shoot controls are reversed.

When dying, if either survives, transforms into a ghost player.
(It means that they won't die at the same time like Jacob and Esau, and can even revive after Boss Room)

They will keep their features even transformed into other characters by some effects.
(Similar to Strawman)

Obviously, if want to get their completion marks, do not transform both of them.

Play as Cain / Tainted Cain, sacrifice for 12 times in a level, and then use Re-death in the graveyard of Dark Room (Do not drop Abel).

The following special synergies and interactions for Benighted Cain and Abel have been documented.

* Note that not all possible synergies and interactions are listed here.

To unlock below, must play on Hard Mode.

• Heart: Re-death
• Isaac: Rabbit Head
• ???: Unwelcome Sacrifice
• Satan: The Left Foot
• Lamb: Welcome Sacrifice
• Mega Satan: Seed Bag
• Boss Rush: Ether
• Hush: Falsehood of Cain Falsehood of Abel
• Delirium: Portable Farm Goatify Wheat Seeds
• Mother: Nemesis
• Beast: Super B
• Greed: Barren
• FINISHED: Deligence & Diligence (mini-boss) Abel is surely dead, this "Abel" is imagined.
(This can be more obvious at the level transition animation)

When firstly added into the game, Re-death is the pocket active to switch between.
(Definitely must be removed since its poor controls)

This is a reference to Omori.

• Download Benighted Soul from the Steam Workshop.