"Supernatural" season 10 ended with a bang and with season 11 confirmed and on its way, reports are coming in on what the Winchester brothers will have to deal with moving forward. As fans will recall, the Mark of Cain has been obliterated, but at a price so high that it may endanger the rest of mankind. 

During the finale of season 10, Dean and Sam almost made a deal with Death himself. The former was going to get locked up forever so that the Mark can't be used against anyone else. However, to ensure that he wouldn't escape, he'd have to kill his brother Sam. 

Sam seemed okay with it but at the last second, the brothers turned the tables and killed Death. At the same time, the witch Rowena removed the Mark from Dean while casting a curse on Crowley and Castiel, forcing the latter to kill the former. However, according to the IBTimes, the show is quite famous for never truly killing off characters so it is very likely both Castiel and Crowley will return in season 11 as they deal with each other and with the curse laid upon them by Rowena. 

The big catch, however, is that the Mark is gone and it wasn't passed to someone else, the way it was meant to. As pointed out in a report by the IBTimes, it was designed to seal a pre-God evil known only as Darkness. Now that the seal has been broken, this evil is running rampant all over the Earth. 

Fans are speculating that this Darkness might not have a physical form but could be a primordial being and may even be the "beginning of time." 

Season 11 will see the Winchester brothers fighting Darkness and perhaps Dean's demonic powers might prove to be of good use here. The battle won't be easy as the brothers still have to deal with other supernatural forces, with Rowena being in the forefront.