Board Thread:Legitimate Canon Questions/@comment-75.118.201.227-20140401040010/@comment-4091815-20140401041632

Her immunity and her Banshee status are never linked definitively.

The nexus stuff is in YOUR head. Peter left memories in Lydia's just like Werewolves do with the nails to the back of the neck thing.

Werewolves are the ones who can "get into" heads. Lydia couldn't have done it without Scott acting as conduit.