That would be a good time to look about. I would look for the book, but not ask directly about it. If I have heard of it, it might be unnecessarily infamous to someone like him. He might try to keep you from reading it.
All you need know about Mephisto is that he is rather unpleasant, likes wine, and deals in the trafficking of souls. Your Midgardian concept of Hell is actually a dimension that has a habit of encroaching onto many others.
That name you were called sounds ominous. If you were in the Darkhold, it might recount some sins of some sort? You did not strike me as the type to do anything untoward without provocation though.
You say this woman attacked you, but you learned from her. You should write down anything you remember, while it is still fresh. What is you learned? Was there a specific type of magic she used, that you were able to take notice of?
I can on the morrow, if you would like. I appreciate the offer to help, but this is not the first time I've lost track of Thor. Like him showing up intrusively at the end of my play. About myself.