User blog:Twilight Despair 5/A (Cure) or whatever for the Mark of Cain

Metatron's small clue about the Mark The river ends at its source. It took sometime but I have deciphering a few theories

1. By source could be the first evil or sin that was truly introduced into the human race. Adam and Eve's action with devouring fruit from the Tree of the Knowledge of Good and Evil. Dean, might need something from this period which is linked to the Tree or maybe Adam himself. (Hell I wouldn't be surprised if Adam was still alive. And was given a great power or a curse from eating the forbidden fruit, like Cain with his Mark of Cain.)

2. By source it might meant Abel. Maybe blood of Abel or something else can undo the Mark.

3. Maybe it might have to with the owner of the Mark's first kill.

It's my theories.