Of course, as a yardslave you are very unlikely to last more than a month, let alone a year, but the Warmweed makes it worse by taking away every chance of recovery.
Growing the Beard: The series becomes increasingly well-written, original, and funny - with a major leap in stylistic quality between books six and seven.
Narm: The Kalkara. They're actually described in-universe as bear assassins.
Nightmare Fuel: Warmweed. This is a plant that essentially mindwipes you after a few doses, is apparently quite common and easy to get, and was distributed to most of the Skandian yard slaves for a very long time.
Shown Their Work: Most of the author's explanations on archery, culture and battle tactics is generally correct, if occasionally somewhat simplistic. But it crosses into Nightmare Fuel when he writes a chillingly accurate portrayal of exactly what it's like to virtually die of dehydration, and just how easily it can happen to anyone who doesn't know the desert.
Tear Jerker: The Royal Ranger book begins with a time skip in which a lot of things have changed. Starting with Alyss being dead.