Board Thread:False Info and Speculative Discussion/@comment-24.130.28.230-20150721180826/@comment-4091815-20150722013851

Nothing supernatural can cross mountain ash in the Teen Wolf Universe.

Lydia is completely unaffected by Mountain Ash.

Lydia is not supernatural.

The show defines the canon. While it's been pretty clear for a long time that Lydia is not like the supernaturals on the show, it is now established canon.