Q:

What are the extra weapon/trap slots for?

In Orcs Must Die!, in both the spellbook and upgrade page, there are extra slots left over after finishing the story on War Mage, and after playing through a few levels of Nightmare mode, it doesn't seem that there are any new traps/weapons coming.
Are these spare slots left there for future DLC, or is there a way to unlock these new weapons that I'm just missing?

A:

These are just spare slots. The items doesn't exist yet, and are most likely to be included in future updates or DLC.

