Simon's just backing away, crossing himself, as I remind him that that's not a thing on Azeroth. We'll work on it. How do you think Simon would be likely to encounter Arthas in this AU, if we threaded them?

Would Emilia be fighting at any of the Legion invasions? That would always be a convenient faction-neutral meeting place if Simon were to run into her, and it would make him ever so slightly less hostile. Probably. Maybe not if they were in Hillsbrad. But anywhere else, he'd be something resembling civil.