- The masked bending thief, who can appear seemingly out of nowhere and vanish just as quickly. Not helped by the fact the disguise is reminiscent of a Plague Doctor. Its like they were specifically trying to invoke this very trope. Even worse is the understanding that behind the mask the could be anyone... even those they might have considered friends...
- The walking dead aren't exactly pleasant to behold either, whenever they appear the story instantly becomes much more serious. They can't be reasoned with or bargained, only fled or fought, and they rack up damage but keep on fighting until totally reduced to paste or ash.
- Korra's nightmare about her four previous foes attacking her, then melting into black slime and re-forming into her new enemy, able to wield all four elements while she is powerless, all while Vaatu is taunting from the background.
- The Reveal about Temuji and Fumikos plans. To really and truly bring the dead back to life. Korra herself is horrified at the prospect, and declares that no one should have that sort of power. Whether or not they can succeed quickly becomes irrelevant.
- The enemy's exact identity remaining a mystery, and having infiltrated at least the White Lotus and the police of a major city, coming dangerously close to killing Ban and his friends numerous times before the first book is even over. No hints to their identity, motive, or organization. A far cry from the readily visible Mooks of the Fire Nation, or even the Affably Evil Red Lotus. Who can you trust when anyone could be out to get you?
- In Book Two's opening chapter, the Band find their way to the uncle of Meiling as a potential firebending teacher, and at the very least, a safe harbor. Yet who should they find behind the door of his manor but Drago, the same Drago who brutally murdered Jade one chapter prior? And they have no idea they're now under the same roof as a ruthless murderer.
- Meiling discovers she has a rare talent to combustionbend, but discovers this at the worst possible time, nearly blowing up herself and her friends by accident. Her subsequent Freak Out over it almost makes it worse.
- Throughout Book Two, Ban's Visions of Korra have a specific thread... telling the story of how their greatest enemy came to be. One that can't ever be truly stopped.