Board Thread:False Info and Speculative Discussion/@comment-67.162.31.47-20140715100605/@comment-49.149.139.111-20140724073210

Allison died before Aiden, so it may be someone who died after him. But it may not have been shown on tv.

It can be Nogitsune... though not killed but was defeated last.

Or Isaac/Ethan/Danny... someone might have killed one of them after season 3.