"Casting will always be interuppted [sic] upon receiving direct damage."

[KoujiGeki]

I'm so glad you're talking about this as if you've experienced it. When did you get a chance to play something no one else has?

its not rocket science, and its in the notes that Hitting is an interrupt and mages have a cone of sight, and they cant move and cast, it wont be hard to exploit. Imagine Dark Souls if you will will the stabbing from the side and using the lag to pull off a backstab