I ... spent a long time staring at the puzzle.
I do like word puzzle like this and I personally think it's a good idea to combine puzzle with defense game, BUT on the other hand I don't like feeling stressed out for unable to find the words when I need them the most. :))
To be honest, the most annoying experience in this game is when I finally managed to summon a knight when there's no enemy and the knight just walk away leaving my fortress unguarded. What the heck, orc knight, you could just say directly if you want me to raise your pay! Don't be passive agressive like that. :v
Btw. I assume from the game title that player plays as an author/writer, which is a good interpretation for the limitation. Good work. :D