Well, that was unexpected.
OK, there was a lot that wasn’t unexpected. Fisher coming back as a Deadite? Expected. Two of those hikers getting killed in a gruesome way? Totally expected. Though Undead Fisher using them as puppets was a nice touch. Ruby popping up and being a badass? She’s Lucy Lawless. Of course she was a badass.
Ash getting Kelly and Pablo to kill the correct Ash? Yeah, that worked. Sure, there were two identical Ashes who knew stuff, but the key wasn’t to see which one was racist (they both kinda were), it was to see which one would tell the others to kill both of them. That doesn’t mean anything, since Kelly reasons the only reason Ash would do that is not out of a sense of noble self-sacrifice, but because he does everything the lazy way to help himself and that would have ended everything very quickly.
And true, Ash does screw up dismembering the corpse of the other Ash since the blood makes the Necronomicon talk, but that’s not the unexpected part.
The unexpected part is Ruby wants the book, and she claims to know how to destroy it.
Step one: cut the face off. Done!
Step two: give Ruby the book. Sure, that means Ash can be a nobody, and he doesn’t care for that, but he does, and then she starts reading from it and stuff gets freaky.
And then the face cut off the book is attracted to Pablo’s charm necklace that he took from his brujo uncle and attaches itself to Pablo, taking over his body.
Oh, but as Ash suggests Ruby doesn’t really know what the book does, she corrects him. She knows exactly what the book does.
She wrote the damn thing!