Board Thread:General Discussion/@comment-11464223-20151109020125/@comment-27187133-20151110095915

Perhaps the vault was created by Nimue or other Dark One to preserve itself, to hide stuff, including the daga. Also, it looks like the dagger at the beginning could kill the DO and stop that because if Merlin was going to kill Nimue but then he couldn't, so I think, if the dagger at that moment would transfer DO essence to its killer, Merlin would be taking the most stupid decision in his life turning himself as a new DO. Perhaps later the DO modifies the "rules" of the Dagger to transfer from a person to other by being "killed".