Robin Hood: Ghosts of Sherwood (movie, 2011)

After selling his soul to a sorceress Robin is killed in battle. Distraught over these horrific turn of events Marian and Little John attempt to resuscitate Robin and his Merry Men. In doing so they inadvertently have turned the one-time heroes into the living dead and worse, the ghostly reincarnations are now hunting down Marian and Little John. So the pair attempt to seek out a new potion that will free these tormented souls from their demonic possession.