Sam and Cain

Alternate ending to season 9, following on directly from 'Stairway to Heaven.' The Mark of Cain is making Dean savage and irrational. Whilst the memory of his brotherhood with Sam remains it is a twisted version of its former self. Dean wants to leave Gadreel and Cass behind and hunt Metatron with Sam, but it is obvious that with the Mark Dean poses a threat to Sam as well.