Looks like whatever happened to Erin cost her both her skills and sanity. Really looking like her memory was altered as she is blaming him for losing everything but it was the Dalki that killed her parents and Truedream who took her ability. Quinn and Leo gave her both power, friends and a family.
It's great seeing Leo go toe to toe with Erin, proving why she is still the student and him the master, even with her Demon tier Sword and Dhampir powers, but we all should of known that something would happen that would change the outcome.
What on earth did Leo take from her? Did her memory get altered by that ability user? I hope Zero truly doesn't interfere. Leo doesn't seem to realize that Erin needs to die. This is going to be sad.
I feel like it's going to be something along the lines of Leo choosing to help another shelter instead of where here parents were and she found out and now blames Leo for her loss...