That's right. Some rat-weasel guessed it already.
However, I decided that it might be nice to give you reader-folk the option of working it out on your own, while relieving the tension of that minority of people in the world who won't sleep until they get it.
This is the answer. No clicky unless you want to spoil it for yourself!
I'll keep posting on a weekly basis until the series is done, and will continue to answer questions and give out hints. A summary of progress so far:
-The correct answer is less than twelve characters long.
-There will be twelve illustrations when I'm finished.
- Not 'headgear,' 'mentorship,' 'party,' or 'pair'.
- However, the illustrations can (and probably should) be grouped into pairs, and most of them will have a pair of things in them.
- As suggested above, #3 and #4 can both be called 'knights'.