Maghda isn't even a demon... she's just a human with a stupid hat.
I like how they showed that Cain had indeed aged twenty years since D2, but at the same time, I felt like his death was really forced. Especially with how dumb Maghda was: FIX THE SWORD! NO?! FINE, DIE! ...except herp, now no one can fix the sword, idiot, and Belial gets nothing but a matching set of fancy paper weights. If anything, she should have killed Leah.
Speaking of which, Leah not believing the stories of Hell was kind of weird. I mean, everyone else in the world seems to know that Hell and demons are legit things, even just as concepts because they've never seen either. But Leah, she seems to completely think that zombies and skeletons and all kinds of weird shit is normal but then... demons? TOTAL CROCK, CAIN!