Symbolism, Imagery, Allegory
Binding Blade
Every hero of a fantasy story needs a magical artifact. Frodo has the One Ring. Daenerys Targaryen has her dragon eggs. And Harry Potter has enough magical gadgets to fill a few aisles at the Hogwarts branch of Toys 'R' Us. Nick doesn't want to be left out, so he gives himself a couple of dazzling artifacts, too.
Yes, we said "gives himself." Ambrose, who is a future version of Nick, gives Nick two magical artifacts: a book and a sword. How did Ambrose get them? Did he get them because a future version of himself gave them to him, too? We have no idea how time travel works. The only thing guaranteed about time travel is that it gives you a migraine.
But time travel isn't the point here. The point is the magical artifacts. First, the blade. According to Ambrose, "It can be a sword, a dagger, or a knife" (16.77). Versatility is this weapon's biggest strength. It can be shrunk to pocket size and increased in length to fit any situation…any situation in which zombies need beheading, that is.
What else can the blade do? Can it grow jagged edges in case Nick wants to be a lumberjack? Can it shrink to the size of a letter opener to help Nick answer Kyrian's correspondence? We'll have to wait and see.
Grim Grimoire
Ambrose also gives Nick a book. Not only can this help pass the time while Nick is waiting in line at the grocery store, but it also tells the future. At least in theory. That's what it's supposed to do.
The thing is that the grimoire needs blood to operate. Why? Because magical reasons. Nick must prick his finger (another good use for his blade), and if he touches the book with the pricked finger, the book will give him advice.
Does it also measure his blood sugar?
The bloodsucking book has an attitude, though. Its advice is cryptic and sarcastic, as if it were written by a vampiric, clairvoyant David Sedaris. When Nick asks it how to get out of a cage, the book totally says, "Here you are and here you'll stay/until you learn a better way" (17.86). Wow, thanks for the help. Nick would be better off asking a Magic 8 Ball for life hacks. It would be less sassy.