User blog:Fusedtwilight/Lucifer and his Mark of Cain

So we found out in season 10 that the reason Lucifer went bad was because God gave him the Mark to keep the Darkness locked away but it was able to corrupt him. It has also been said that Lucifer didn't just give it to Cain nor did Cain just give it to Dean, it was copied onto them. So since Cain was killed and it was removed from Dean then shouldn't the Darkness still be locked away because Lucifer would still have had it.

Or could it be that the spell to remove the Mark didn't just removed it from Dean but also Lucifer even though he is in hell?

If that is the case maybe Lucifer will turn good and both he and Michael can help the brothers fight the Darkness.